allenai/sciq · Datasets at Hugging Face

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During adolescence, what causes most of the changes associated with puberty?	methane	estrogen	nicotine	testosterone	During adolescence, testosterone causes most of the changes associated with puberty. It causes the reproductive organs to mature. It also causes other adult male traits to develop. For example, it causes the voice to deepen and facial hair to start growing.
What is essential for cellular respiration for all aerobic organisms?	carbon	nitrogen	water	oxygen	An online guide from the University of Illinois about air masses and fronts is found here: http://ww2010. atmos. uiuc. edu/%28Gh%29/guides/mtr/af/home. rxml .
Breeding in birds occurs through an internal type of what process?	stimulation	segmentation	sedimentation	fertilization	Breeding in birds is through internal fertilization, where the egg is fertilized inside the female.
In an endothermic reaction, what is absorbed by the reaction?	atoms	food	fuel	energy	Because energy is a product, energy is given off by the reaction. Therefore, this reaction is exothermic. Because energy is a reactant, energy is absorbed by the reaction. Therefore, this reaction is endothermic.
What scientist and monk is best known for his experiments with pea plants?	aristotle	steiner mendel	charles darwin	gregor mendel	Gregor Mendel was born in 1822 and grew up on his parents’ farm in Austria. He did well in school and became a monk. He also went to the University of Vienna, where he studied science and math. His professors encouraged him to learn science through experimentation and to use math to make sense of his results. Mendel is best known for his experiments with the pea plant Pisum sativum (see Figure below ). You can watch a video about Mendel and his research at the following link: http://www. metacafe. com/watch/hl-19246625/milestones_in_science_engineering_gregor_mendel_and_classical_genetics/ .
What are structures that protect the coast like barrier islands called?	fortresses	domes	dunes	breakwaters	Breakwaters are structures that protect the coast like barrier islands. Groins are structures that help prevent longshore drift from eroding a beach.
What leads to multiple copies of a chromosomal region?	subtractions	minimilizations	gene modification	duplications (or amplifications )	Duplications (or amplifications ) lead to multiple copies of a chromosomal region, increasing the number of the genes located within that region. Some genes may be duplicated in their entirety.
The larger surface area of leaves allows them to capture more what?	chlorophyll	pollen	molecules	sunlight	Roots: Support for the Plant Roots are not well preserved in the fossil record; nevertheless, it seems that they did appear later in evolution than vascular tissue. The development of an extensive network of roots represented a significant new feature of vascular plants. Thin rhizoids attached the bryophytes to the substrate. Their rather flimsy filaments did not provide a strong anchor for the plant; neither did they absorb water and nutrients. In contrast, roots, with their prominent vascular tissue system, transfer water and minerals from the soil to the rest of the plant. The extensive network of roots that penetrates deep in the ground to reach sources of water also stabilizes trees by acting as ballast and an anchor. The majority of roots establish a symbiotic relationship with fungi, forming mycorrhizae. In the mycorrhizae, fungal hyphae grow around the root and within the root around the cells, and in some instances within the cells. This benefits the plant by greatly increasing the surface area for absorption. Leaves, Sporophylls, and Strobili A third adaptation marks seedless vascular plants. Accompanying the prominence of the sporophyte and the development of vascular tissue, the appearance of true leaves improved photosynthetic efficiency. Leaves capture more sunlight with their increased surface area. In addition to photosynthesis, leaves play another role in the life of the plants. Pinecones, mature fronds of ferns, and flowers are all sporophylls—leaves that were modified structurally to bear sporangia. Strobili are structures that contain the sporangia. They are prominent in conifers and are known commonly as cones: for example, the pine cones of pine trees.
What is connected to, and dependent on, the gametophyte?	the zygote	the sperm	the chromosomes	the sporophyte	Following fertilization, the sporophyte forms. The sporophyte is connected to, and dependent on, the gametophyte.
After passing through capillaries and being filtered, clean blood leaves what organ through a vein?	heart	pancreas	liver	kidney	Blood with wastes enters each kidney through an artery, which branches into many capillaries. After passing through capillaries and being filtered, the clean blood leaves the kidney through a vein.
What kind of medical intervention seeks to eradicate diseases like polio and measles?	malnutrition	surgical intervention	nutrition	vaccination
The ostrich, kiwi, rhea, cassowary, and moa are examples of what kind of birds?	prehistoric	predators	raptors	flightless	Some birds have lost the ability to fly during the course of their evolution. Several flightless birds are shown in Figure below . They include the ostrich, kiwi, rhea, cassowary, and moa. All of these birds have long legs and are adapted for running. The penguins shown in the figure are also flightless birds, but they have a very different body shape. That’s because they are adapted for swimming rather than running.
What occurs when individuals of different species strive for a limited resource in the same area?	intraspecific competition	vegetal competition	asexual competition	interspecific competition	Interspecific competition happens when individuals of different species strive for a limited resource in the same area. Since any two species have different traits, one species will be able to out-compete the other. One species will be better adapted to its environment, and essentially "win" the competition. The other species will have lower reproductive success and lower population growth, resulting in a lower survival rate. For example, cheetahs and lions feed on similar prey. If prey is limited, then lions may catch more prey than cheetahs. This will force the cheetahs to either leave the area or suffer a decrease in population.
Most fungi reproduce asexually by producing what?	toxins	seeds	ions	spores	Almost all fungi reproduce asexually by producing spores. A fungi spore is a haploid cell produced by mitosis from a haploid parent cell. It is genetically identical to the parent cell. Fungi spores can develop into new haploid individuals without being fertilized.
Alchemists, as early as the eighth century, knew nitric acid as aqua fortis, which means?	applied water	isolated water	clean water	strong water	Nitrogen Oxyacids and Salts Nitrogen pentaoxide, N2O5, and NO2 react with water to form nitric acid, HNO3. Alchemists, as early as the eighth century, knew nitric acid (shown in Figure 18.50) as aqua fortis (meaning "strong water"). The acid was useful in the separation of gold from silver because it dissolves silver but not gold. Traces of nitric acid occur in the atmosphere after thunderstorms, and its salts are widely distributed in nature. There are tremendous deposits of Chile saltpeter,.
Particles of sand and what other substance are carried by longshore drift?	soil	magma	bone	rock	Longshore drift carries particles of sand and rock down a coastline.
Most reptiles reproduce sexually and have what type of fertilization?	mechanical	additional	external	internal	Most reptiles reproduce sexually and have internal fertilization.
What is type of substance is formed when water vapor condenses or when ice melts?	gaseous water	toxic water	chemical water	liquid water	Liquid water is formed when water vapor condenses (i. e. , H 2 O(g) → H 2 O(l) or when ice melts (i. e. , H 2 O(s) → H 2 O(l)). Because water is a molecular substance, it is a poor conductor of electricity in its pure form. However, as we will see later, its conductivity can be improved by the addition of certain substances. Water molecules are polar, and this overall polarity gives rise to many of the properties of water. For example, an interesting effect is seen when water is placed in a static electric field, as shown in the Figure below and the video below. This phenomenon can be explained in terms of the polarity of water molecules.
What occur because solid lithosphere travels on a round planet?	ejecta earthquakes	aeration earthquakes	volcanos	intraplate earthquakes	Intraplate earthquakes occur because solid lithosphere travels on a round planet.
What is the unit of evolution?	biome	species	community	population	Remember that individuals do not evolve. Their genes do not change over time. The unit of evolution is the population. A population consists of organisms of the same species that live in the same area. In terms of evolution, the population is assumed to be a relatively closed group. This means that most mating takes place within the population. The science that focuses on evolution within populations is population genetics . It is a combination of evolutionary theory and Mendelian genetics.
The boiling points of liquid also correlate to the strength of which forces?	gravitational	centrifugal	supramolecular	intermolecular	The boiling points of liquid also correlate to the strength of the intermolecular forces. Recall that diethyl ether has weak dispersion forces, which meant that the liquid has a high vapor pressure. The weak forces also mean that it does not require a large an input of energy to make diethyl ether boil and so it has a relatively low normal boiling point of 34.6°C. Water, with its much stronger hydrogen bonding, has a low vapor pressure and a higher normal boiling point of 100°C.
Vitamin d is made in the skin when it is exposed to what?	dirt	darkness	water	sunlight	Vitamins are organic compounds that the body needs in small amounts to function properly. Humans need 16 different vitamins. Six of them are listed in Table below . Vitamin D is made in the skin when it is exposed to sunlight. Bacteria that normally live in the gut make vitamins B12 and K. All other vitamins must come from food. The table shows good food sources of the vitamins.
Of the three basic types of radioactive emissions, what particle is the most penetrating?	beta	neutron	alpha	gamma	The various emissions will differ considerably in their ability to go through matter, known as their penetrating ability . The α-particle has the least penetrating power since it is the largest and slowest emission. It can be blocked by a sheet of paper or a human hand. Beta particles are more penetrating than alpha particles, but can be stopped by a thin sheet of aluminum. Of the three basic types of emissions, gamma particle are the most penetrating. A thick lead shield is required to stop gamma emissions. Positrons represent a special case in that they annihilate when they come in contact with electrons. The collision of a positron and an electron results in the formation of two gamma emissions that go 180 degrees away from each other.
Which ocean zone is the narrow strip along a coastline that is covered by water at high tide and exposed to air at low tide?	deep zone	miniscule zone	calcareous zone	intertidal zone	One of the most familiar ocean zones is the intertidal zone. This is the narrow strip along a coastline that is covered by water at high tide and exposed to air at low tide. You can see an example of an intertidal zone in Figure below . There are plenty of nutrients and sunlight in the intertidal zone. Producers here include phytoplankton and algae. Other organisms include barnacles, snails, crabs, and mussels. They must have adaptations for the constantly changing conditions in this zone.
Elongation is the addition of what to the mrna strand?	filaments	codons	glycine	nucleotides	Elongation is the addition of nucleotides to the mRNA strand.
What is the distance north or south of the equator called?	Prime Meridian	inclination	longitude	latitude	Latitude is the distance north or south of the equator. It’s measured in degrees, from 0° to 90°. Several climate factors vary with latitude.
The force exerted by a diving board is conservative, provided the internal friction is this?	significant	static	intrinsic	negligible	7.4 Conservative Forces and Potential Energy 9. What is a conservative force? 10. The force exerted by a diving board is conservative, provided the internal friction is negligible. Assuming friction is negligible, describe changes in the potential energy of a diving board as a swimmer dives from it, starting just before the swimmer steps on the board until just after his feet leave it. Define mechanical energy. What is the relationship of mechanical energy to nonconservative forces? What happens to mechanical energy if only conservative forces act? 12. What is the relationship of potential energy to conservative force?.
Along with other elements, most ores are made of what?	sodium	coal	crystals	metal	When the ore leaves the mine, it is not yet a useful material ( Figure below ). Most ores are a combination of metal and other elements. The rocks are full of valuable minerals. They also contain rock that isn't valuable, which is called waste rock. The valuable minerals must be separated from the waste rock.
The bottoms—but not the tops—of the wave slow down because of what?	temperature	size	vibration	friction	In shallow water close to shore, waves start to drag on the bottom of the water. The bottoms—but not the tops—of the wave slow down because of friction. This causes the waves to steepen until they break and fall over, carrying water onto the shore as surf.
Molecular geometry is the three-dimensional arrangement of atoms in a what?	nucleus	genes	DNA	molecule	Molecular geometry is the three-dimensional arrangement of atoms in a molecule. The molecular geometry, or shape, of a molecule is an important factor that affects the physical and chemical properties of a compound. Those properties include melting and boiling points, solubility, density, and the types of chemical reactions that a compound undergoes. In this lesson, you will learn a technique to predict molecular geometry based on a molecule’s Lewis electron dot structure.
What mineral is used to produce glass?	pyrite	lead	feldspar	quartz	Silver is used to make sterling silver jewelry. Table salt is the mineral halite. Glass is produced from the mineral quartz.
What is caused by atoms or ions when they share or transfer valance electrons?	force of repulsion	loss of charge	gain of charge	force of attraction	No, not all birds can fly. And not all birds have wings. This penguin is a good example. Their wings have evolved into flippers, adapted for swimming instead of flying. The kiwi of New Zealand is another bird without wings.
Due to the time it takes for light to reach us, galaxies at the edge of the universe are distant in terms of space and what else?	energy	gravity	temperature	time	The galaxies at the edge of the Universe are a great distance away. But they are something else that is distant. Because it takes so long for light from so far away to reach us, they are also very far back in time ( Figure below ).
Some membrane proteins that actively transport ions contribute to what?	cellular potential	organism potential	protein potential	membrane potential
In which human organ do the juveniles develop into sexually mature adults?	muscles	liver	tissues	intestines
Both sexes of sockeye salmon turn red with green heads just prior to what?	migrating	dying	feeding	spawning	Wild male and female Sockeye salmon before spawning. Sockeye salmon are blue tinged with silver in color while living in the ocean. Just prior to spawning, both sexes turn red with green heads. Sockeye spawn mostly in streams having lakes in their watershed. The young fish spend up to three years in the freshwater lake before migrating to the ocean. Migratory fish spend from one to four years in salt water, and thus are four to six years old when they return to spawn. Navigation to the home river is thought to be done using the characteristic smell of the stream, and possibly the sun.
While the numerical aperture can be used to compare resolutions of various objectives, it does not indicate how far the lens could be from the what?	focal point	microscope	diameter	specimen	While the numerical aperture can be used to compare resolutions of various objectives, it does not indicate how far the lens could be from the specimen. This is specified by the “working distance,” which is the distance (in mm usually) from the front lens element of the objective to the specimen, or cover glass. The higher the NA the closer the lens will be to the specimen and the more chances there are of breaking the cover slip and damaging both the specimen and the lens. The focal length of an objective lens is different than the working distance. This is because objective lenses are made of a combination of lenses and the focal length is measured from inside the barrel. The working distance is a parameter that microscopists can use more readily as it is measured from the outermost lens. The working distance decreases as the NA and magnification both increase.
Energy from the sun has a wide range of wavelengths.what is the total range of energy called?	thermal spectrum	heat spectrum	light spectrum	electromagnetic spectrum	Energy from the Sun has a wide range of wavelengths. The total range of energy is called the electromagnetic spectrum . You can see it in Figure below .
When something loses electrons, it must also?	gain protons	reduce protons	slow down	gain electrons	Solution The charges, as well as the atoms, must balance in reactions. The silver atom is being oxidized from the 0 oxidation state to the 1+ state. Whenever something loses electrons, something must also gain electrons (be reduced) to balance the equation. Oxygen is a good oxidizing agent for these reactions because it can gain electrons to go from the 0 oxidation state to the 2− state.
Water and chemical elements that organisms need keep recycling through biogeochemical what?	effects	mutations	levels	cycles	Water and chemical elements that organisms need keep recycling through biogeochemical cycles. These cycles include biotic and abiotic components of ecosystems.
What is the most abundant biochemical compound, making up the cell walls of plants?	mitochondria	magnesium	cytoplasm	cellulose	Cellulose is the most abundant biochemical compound. It makes up the cell walls of plants and gives support to trunks and stems. Cellulose also provides needed fiber in the human diet. We can’t digest cellulose, but it helps keep food wastes moving through the digestive tract.
What organisms use cilia, pseudopods, or flagella to move?	prokaryotes	bacteria	arthropods	protists	Protists use cilia, pseudopods, or flagella to move.
During which phase do sister chromatids separate and the centromeres divide?	passivation	cell phase	gap cycle	anaphase	During anaphase , sister chromatids separate and the centromeres divide. The sister chromatids are pulled apart by the shortening of the spindle fibers. This is like reeling in a fish by shortening the fishing line. One sister chromatid moves to one pole of the cell, and the other sister chromatid moves to the opposite pole. At the end of anaphase, each pole of the cell has a complete set of chromosomes.
What term describes a type of redox reaction in which the same substance is both oxidized and reduced?	misappropriation	interposition	disapprobation	disproportion	Disproportion is a type of redox reaction in which the same substance is both oxidized and reduced. Identify the element that is disproportionating and indicate the initial and final oxidation numbers of that element. 2CuCl(aq) → CuCl2(aq) + Cu(s) Saylor URL: http://www. saylor. org/books.
Each organism inherits one of what item for each gene from each parent?	cell	molecule	phenotype	allele
What term is used to refer to the external female reproductive structures collectively?	uterus	cervix	vagina	vulva	External Female Genitals The external female reproductive structures are referred to collectively as the vulva (Figure 27.10). The mons pubis is a pad of fat that is located at the anterior, over the pubic bone. After puberty, it becomes covered in pubic hair. The labia majora (labia = “lips”; majora = “larger”) are folds of hair-covered skin that begin just posterior to the mons pubis. The thinner and more pigmented labia minora (labia = “lips”; minora = “smaller”) extend medial to the labia majora. Although they naturally vary in shape and size from woman to woman, the labia minora serve to protect the female urethra and the entrance to the female reproductive tract. The superior, anterior portions of the labia minora come together to encircle the clitoris (or glans clitoris), an organ that originates from the same cells as the glans penis and has abundant nerves that make it important in sexual sensation and orgasm. The hymen is a thin membrane that sometimes partially covers the entrance to the vagina. An intact hymen cannot be used as an indication of “virginity”; even at birth, this is only a partial membrane, as menstrual fluid and other secretions must be able to exit the body, regardless of penile–vaginal intercourse. The vaginal opening is located between the opening of the urethra and the anus. It is flanked by outlets to the Bartholin’s glands (or greater vestibular glands).
Which state of matter has the lowest density?	solids	liquids	fluids	gases	Gases have much lower densities than liquids and solids. For example, liquid water is over 1000 times more dense than water vapor at STP.
Skeletal, cardiac, and smooth are the three types of what cells and possess morphologies correlated with their functions?	bone	cartilage tissue	organ	muscle	4.4 Muscle Tissue and Motion The three types of muscle cells are skeletal, cardiac, and smooth. Their morphologies match their specific functions in the body. Skeletal muscle is voluntary and responds to conscious stimuli. The cells are striated and multinucleated appearing as long, unbranched cylinders. Cardiac muscle is involuntary and found only in the heart. Each cell is striated with a single nucleus and they attach to one another to form long fibers. Cells are attached to one another at intercalated disks. The cells are interconnected physically and electrochemically to act as a syncytium. Cardiac muscle cells contract autonomously and involuntarily. Smooth muscle is involuntary. Each cell is a spindle-shaped fiber and contains a single nucleus. No striations are evident because the actin and myosin filaments do not align in the cytoplasm.
What do glands in the skin produce to cool down the body?	mucus	lactic acid	saliva	sweat	glands in the skin that produce sweat, a salty fluid that helps cool down the body.
The only obvious difference between boys and girls at birth is what type of organs?	nervous	digestive	respiratory	reproductive	The only obvious difference between boys and girls at birth is their reproductive organs. However, even the reproductive organs start out the same in both sexes.
Mammals have a number of kinds of thermoreceptors, each specific for a particular what?	weight range	electrical range	oxygen range	temperature range
With a shape that specially suits its function of sending nerve signals to other cells, the human nerve cell is an example of what?	evolution	adaptation	maturation	specialization	The human nerve cell in Figure below is a good example of a specialized animal cell. Its shape suits it for its function of sending nerve signals to other cells. A nerve cell couldn’t take this shape if it were surrounded by a rigid cell wall.
What is defined as the mass per unit volume of a substance?	height	weight	diameter	density	As you know, density is defined as the mass per unit volume of a substance. Since gases all occupy the same volume on a per mole basis, the density of a particular gas is dependent on its molar mass. A gas with a small molar mass will have a lower density than a gas with a large molar mass. Gas densities are typically reported in g/L. Gas density can be calculated from molar mass and molar volume.
What reaction means, literally, “splitting with water"?	fission	aqueous	hydroxis	hydrolysis	Esters are neutral compounds, unlike the acids from which they are formed. In typical reactions, the alkoxy (OR′) group of an ester is replaced by another group. One such reaction is hydrolysis, literally “splitting with water. ” The hydrolysis of esters is catalyzed by either an acid or a base. Acidic hydrolysis is simply the reverse of esterification. The ester is heated with a large excess of water containing a strong-acid catalyst. Like esterification, the reaction is reversible and does not go to completion.
Approximately how much larger is the radius of an atom than that of its nucleus?	100 times	1 times	1000 times	10 times	The radius of an atom is approximately 10 times larger than the radius of its nucleus. If the radius of the nucleus were 1.0 cm, what would be the radius of the atom in centimeters? in miles?.
What can be worn to protect hands and skin from harm?	filters	splints	masks	gloves
What type of movements are produced when the angle between the bones of a joint changes?	oblong	microscopic	circular	angular	The wide range of movement allowed by synovial joints produces different types of movements. Angular movements are produced when the angle between the bones of a joint changes. Flexion, or bending, occurs when the angle between the bones decreases. Moving the forearm upward at the elbow is an example of flexion. Extension is the opposite of flexion in that the angle between the bones of a joint increases. Rotational movement is the movement of a bone as it rotates around its own longitudinal axis. Movement of the head as in saying “no” is an example of rotation.
What senses the movement of liquid in ear canals?	muscle cells	Ear Drum	Brain Cells	hair cells	This bottle of water models the semicircular canals in your ears. When you tip the bottle, the water moves up or down the sides of the bottle; when you tip your head, the liquid inside the semicircular canals moves up and down the sides of the canals. Tiny hair cells lining the canals sense the movement of liquid and send messages to the brain.
What part of the brain regulates certain hormones associated with reproduction during breeding seasons?	hippocampus	thalamus	frontal lobe	hypothalamus
What is any nonmetallic, inorganic solid that is strong enough for use in structural applications called?	glass	tissue	metallic	ceramic	Ceramics A ceramic is any nonmetallic, inorganic solid that is strong enough for use in structural applications. Traditional ceramics, which are based on metal silicates or aluminosilicates, are the materials used to make pottery, china, bricks, and concrete. Modern ceramics contain a much wider range of components and can be classified as either ceramic oxides, which are based on metal oxides such as alumina (Al2O3), zirconia (ZrO2), and beryllia (BeO), or nonoxide ceramics, which are based on metal carbides such as silicon carbide (carborundum, SiC) and tungsten carbide (WC), or nitrides like silicon nitride (Si 3N4) and boron nitride (BN). All modern ceramics are hard, lightweight, and stable at very high temperatures. Unfortunately, however, they are also rather brittle, tending to crack or break under stresses that would cause metals to bend or dent. Thus a major challenge for materials scientists is to take advantage of the desirable properties of ceramics, such as their thermal and oxidative stability, chemical inertness, and toughness, while finding ways to decrease their brittleness to use them in new applications. Few metals can be used in jet engines, for example, because most lose mechanical strength and react with oxygen at the very high operating.
What is the outer layer of the sun made up of?	gas	oxygen	nitrogen	plasma	outermost layer of the sun, made up of a plasma that extends millions of kilometers into space.
Viruses may damage or kill cells by causing the release of hydrolytic enzymes from where?	glands	capillaries	lipids	lysosomes
Species that have diverged from their common ancestors have greater differences in what?	immunology	life span	cell structure	dna sequence	Evidence from the fossil record can be combined with data from molecular clocks. A molecular clock uses DNA sequences (or the proteins they encode) to estimate relatedness among species. Molecular clocks estimate the time in geologic history when related species diverged from a common ancestor. Molecular clocks are based on the assumption that mutations accumulate through time at a steady average rate for a given region of DNA. Species that have accumulated greater differences in their DNA sequences are assumed to have diverged from their common ancestor in the more distant past. Molecular clocks based on different regions of DNA may be used together for more accuracy.
In a fuel cell, energy is not stored; electrical energy is provided by what?	consumption reaction	fusion reaction	carbon reaction	chemical reaction	called an alkaline battery when adapted to operate under alkaline conditions. Button batteries have a high output-to-mass ratio; lithium–iodine batteries consist of a solid electrolyte; the nickel– cadmium (NiCad) battery is rechargeable; and the lead–acid battery, which is also rechargeable, does not require the electrodes to be in separate compartments. A fuel cell requires an external supply of reactants as the products of the reaction are continuously removed. In a fuel cell, energy is not stored; electrical energy is provided by a chemical reaction.
What substance comes toward earth's crust through mantle plumes?	gas	rocks	water	magma	Some volcanoes form over active hot spots . Scientists count about 50 hot spots on the Earth. Hot spots may be in the middle of a tectonic plate. Hot spots lie directly above a column of hot rock called a mantle plume . Mantle plumes continuously bring magma up from the mantle towards the crust ( Figure below ).
A plant is composed of two main types of tissue: meristematic tissue and what other kind of tissue?	nonvascular tissue	synovial tissue	muscle tissue	permanent tissue	CHAPTER SUMMARY 30.1 The Plant Body A vascular plant consists of two organ systems: the shoot system and the root system. The shoot system includes the aboveground vegetative portions (stems and leaves) and reproductive parts (flowers and fruits). The root system supports the plant and is usually underground. A plant is composed of two main types of tissue: meristematic tissue and permanent tissue. Meristematic tissue consists of actively dividing cells found in root and shoot tips. As growth occurs, meristematic tissue differentiates into permanent tissue, which is categorized as either simple or complex. Simple tissues are made up of similar cell types; examples include dermal tissue and ground tissue. Dermal tissue provides the outer covering of the plant. Ground tissue is responsible for photosynthesis; it also supports vascular tissue and may store water and sugars. Complex tissues are made up of different cell types. Vascular tissue, for example, is made up of xylem and phloem cells.
The smallest and lightest alcohols (methanol, ethanol, propanol) are completely soluble in?	argon	gasoline	oil	water	The smallest and lightest alcohols (methanol, ethanol, propanol) are completely soluble in water in all proportions. In a solution, the hydroxyl groups of alcohol molecules and the water molecules form hydrogen bonds with each other, resulting in complete miscibility. However, as the length of the carbon chain increases, the solubility decreases. The solubility of 1-butanol is 7.4 g per 100 g of water, while that of 1-pentanol is 2.7 g per 100 g water, and 1-octanol is 0.06 g per 100 g water. The carbon chain portion of the larger alcohol molecule is nonpolar and leads to the decreased solubility of the overall compound.
In which stage do chromosomes line up one on top of each other along the middle of the cell, similar to how they line up in mitosis?	chromosome ii	hectase ii	cyclohexane ii	metaphase ii	Metaphase II: The chromosomes line up one on top of each other along the middle of the cell, similar to how they line up in mitosis. The spindle is attached to the centromere of each chromosome.
If the frequency of the electromagnetic wave is the same as the natural frequencies of the system, the transfer of what is much more efficient?	light	heat	sound	energy	24.4 Energy in Electromagnetic Waves Anyone who has used a microwave oven knows there is energy in electromagnetic waves. Sometimes this energy is obvious, such as in the warmth of the summer sun. Other times it is subtle, such as the unfelt energy of gamma rays, which can destroy living cells. Electromagnetic waves can bring energy into a system by virtue of their electric and magnetic fields. These fields can exert forces and move charges in the system and, thus, do work on them. If the frequency of the electromagnetic wave is the same as the natural frequencies of the system (such as microwaves at the resonant frequency of water molecules), the transfer of energy is much more efficient. Connections: Waves and Particles The behavior of electromagnetic radiation clearly exhibits wave characteristics. But we shall find in later modules that at high frequencies, electromagnetic radiation also exhibits particle characteristics. These particle characteristics will be used to explain more of the properties of the electromagnetic spectrum and to introduce the formal study of modern physics. Another startling discovery of modern physics is that particles, such as electrons and protons, exhibit wave characteristics. This simultaneous sharing of wave and particle properties for all submicroscopic entities is one of the great symmetries in nature.
When are nutrients absorbed into the body?	after digestion	after excretion	before digestion	during digestion
What happens to the length of the days in the fall?	they get longer	they stay the same	they change randomly	they get shorter	For example, in the fall, when the days start to get shorter, the trees sense that there is less sunlight. The plant is stimulated, and it sends messages telling the leaves to change colors and fall. This is an example of photoperiodism , the reaction of organisms, such as plants, to the length of day or night. Photoperiodism is also the reaction of plants to the length of light and dark periods. Many flowering plants sense the length of night, a dark period, as a signal to flower. Each plant has a different photoperiod, or night length. When the plant senses the appropriate length of darkness, resulting in an appropriate length of daylight, it flowers. Flowering plants are classified as long-day plants or short-day plants. Long-day plants flower when the length of daylight exceeds the necessary photoperiod, and short-day plants flower when the day length is shorter than the necessary photoperiod. Long-day plants include carnations, clover, lettuce, wheat, and turnips. Short-day plants include cotton, rice, and sugar cane.
Of the nine classes of vertebrates, how many are fish?	three	one	four	five	Of course. But what type? Of the nine classes of vertebrates, five are fish. Each of the five classes has distinguishing characteristics that allow members to be classified appropriately. Stingray are cartilaginous fish, related to sharks.
After fertilization is complete, no other sperm can enter. the fertilized ovule forms the seed, whereas the tissues of the ovary become this?	vegetables	plant	wheat	fruit	events in angiosperms are known as double fertilization (Figure 32.18). After fertilization is complete, no other sperm can enter. The fertilized ovule forms the seed, whereas the tissues of the ovary become the fruit, usually enveloping the seed.
What is a fluid-filled body cavity that is completely enclosed by mesoderm called?	choroid	pseudocoelom	hymenium	coelom	Later, a true coelom evolved. This is a fluid-filled body cavity that is completely enclosed by mesoderm. The coelom lies between the digestive cavity and body wall. You can see it in the invertebrate in Figure below . Modern invertebrates with a coelom include mollusks (Phylum Mollusca) and annelids (Phylum Annelida).
Which is the least massive outer planet?	jupiter	venus	mars	uranus	Uranus is the least massive outer planet. Its mass is only about 14 times the mass of Earth. Like all of the outer planets, Uranus is much less dense than Earth. Gravity is actually weaker than on Earth’s surface. If you were at the top of the clouds on Uranus, you would weigh about 10 percent less than what you weigh on Earth.
The nervous system is characterized by electrical signals that are sent from one area to another. whether those areas are close or very far apart, the signal must travel along this?	tendons	axial	hairs	axon	12.4 The Action Potential The nervous system is characterized by electrical signals that are sent from one area to another. Whether those areas are close or very far apart, the signal must travel along an axon. The basis of the electrical signal is the controlled distribution of ions across the membrane. Transmembrane ion channels regulate when ions can move in or out of the cell, so that a precise signal is generated. This signal is the action potential which has a very characteristic shape based on voltage changes across the membrane in a given time period. The membrane is normally at rest with established Na+ and K+ concentrations on either side. A stimulus will start the depolarization of the membrane, and voltage-gated channels will result in further depolarization followed by repolarization of the membrane. A slight overshoot of hyperpolarization marks the end of the action potential. While an action potential is in progress, another cannot be generated under the same conditions. While the voltage-gated Na+ channel is inactivated, absolutely no action potentials can be generated. Once that channel has returned to its resting state, a new action potential is possible, but it must be started by a relatively stronger stimulus to overcome the K + leaving the cell. The action potential travels down the axon as voltage-gated ion channels are opened by the spreading depolarization. In unmyelinated axons, this happens in a continuous fashion because there are voltage-gated channels throughout the membrane. In myelinated axons, propagation is described as saltatory because voltage-gated channels are only found at the nodes of Ranvier and the electrical events seem to “jump” from one node to the next. Saltatory conduction is faster than continuous conduction, meaning that myelinated axons propagate their signals faster. The diameter of the axon also makes a difference as ions diffusing within the cell have less resistance in a wider space.
What occurs when light reflects off a very smooth surface and forms a clear image?	refraction	projection	absorption	regular reflection	Regular reflection occurs when light reflects off a very smooth surface and forms a clear image. Diffuse reflection occurs when light reflects off a rough surface and forms a blurry image or no image at all.
The head of the sperm contains what, which holds the chromosomes?	eggs	nerve cells	fiber	nucleus	The head of the sperm contains the nucleus. The nucleus holds the chromosomes. In humans, the nucleus of a sperm cell contains 23 chromosomes. The acrosome on the head contains enzymes that help the sperm penetrate an egg.
What system is responsible for defending your body against sickness?	digestion system	nervous system	circulatory system	immune system	Infectious diseases are diseases that spread from person to person. They are caused by pathogens such as bacteria, viruses or fungi. What can you do to avoid infectious diseases? Eating right and getting plenty of sleep are a good start. These habits will help keep your immune system healthy. With a healthy immune system, you will be able to fight off many pathogens. The next best way is to avoid pathogens. Though this is difficult, there are steps you can take to limit your exposure to pathogens.
What effect occurs when a few individuals start, or found, a new population?	pioneer	divergent	convergent	founder	Founder effect occurs when a few individuals start, or found, a new population. By chance, allele frequencies of the founders may be different from allele frequencies of the population they left. An example is described in the Figure below .
Each kidney is supplied by a renal artery and what else?	coronary artery	spinal cord	brain vein	renal vein	Each kidney is supplied by a renal artery and renal vein.
What cell structures capture light energy from the sun and use it with water and carbon dioxide to produce sugars for food?	nuclei	fibroblasts	ribosomes	chloroplasts	Chloroplasts capture light energy from the sun and use it with water and carbon dioxide to produce sugars for food. Chloroplasts look like flat discs and are usually 2 to 10 micrometers in diameter and 1 micrometer thick. A model of a chloroplast is shown in Figure below . The chloroplast is enclosed by an inner and an outer phospholipid membrane. Between these two layers is the intermembrane space. The fluid within the chloroplast is called the stroma , and it contains one or more molecules of small, circular DNA. The stroma also has ribosomes. Within the stroma are stacks of thylakoids , sub-organelles that are the site of photosynthesis. The thylakoids are arranged in stacks called grana (singular: granum). A thylakoid has a flattened disk shape. Inside it is an empty area called the thylakoid space or lumen. Photosynthesis takes place on the thylakoid membrane.
What is released when catabolic pathways break down complex molecules?	food	hydrogen	oxygen	energy
Mass and volume are examples of what kind of properties?	varied properties	dynamic properties	exclusive properties	extensive properties	Mass and volume are examples of extensive properties.
What technique is used by insects and birds to find food, mates, and safety from predators?	mating	playing	sleeping	flying	Other than insects, virtually no other animals can inhabit the airy world. Flying is a sure-fire way to escape from all but the quickest nonflying predators. Flying also gives birds a good view for finding food and mates.
What property of food is determined by burning the food and measuring the heat released?	additives	acidity	nutrients	calories	Food calories are determined by burning the food and measuring the heat released.
What simple machine works with a wheel and axle in a wheelbarrow?	blade	pulley	hammer	lever	Look at the wheelbarrow in the Figure below . It is used to carry heavy objects. It consists of two simple machines: a lever and a wheel and axle. Effort is applied to the lever by picking up the handles of the wheelbarrow. The lever, in turn, applies upward force to the load. The force is increased by the lever, making the load easier to lift. Effort is applied to the wheel of the wheelbarrow by pushing it over the ground. The rolling wheel turns the axle and increases the force, making it easier to push the load.
What type of joint has the greatest range of motion?	Pivot	Hinge	Gliding	ball-and-socket	There are a variety of types of movable joints, which are illustrated in Figure below . The joints are classified by how they move. For example, a ball-and-socket joint, such as the shoulder, has the greatest range of motion, allowing movement in several directions. Other movable joints, including hinge joints such as the knee, allow less movement.
What is the movement of molecules from an area of high concentration of the molecules to an area with a lower concentration?	secretion	absorption	condensation	diffusion	Diffusion is the movement of molecules from an area of high concentration of the molecules to an area with a lower concentration. The difference in the concentrations of the molecules in the two areas is called the concentration gradient . Diffusion will continue until this gradient has been eliminated. Since diffusion moves materials from an area of higher concentration to the lower, it is described as moving solutes "down the concentration gradient. " The end result of diffusion is an equal concentration, or equilibrium , of molecules on both sides of the membrane.
Light-weight air-filled bones and a large four-chambered heart helps a bird do what?	run	swim	digest	fly	Bird organ systems are adapted for flight. For example, they have light-weight air-filled bones and a large four-chambered heart.
The myod protein deserves its designation as a master regulatory what?	enzyme	hormone	protein	gene	Some organisms can reproduce sexually or asexually. Under what conditions might each type of reproduction be an advantage?.
When flagellated sperm must swim to the egg, sexual reproduction requires the presence of what substance?	sunshine	air	nitrogen	water	The male gametophyte produces flagellated sperm that must swim to the egg formed by the female gametophyte. For this reason, sexual reproduction must happen in the presence of water. Therefore, nonvascular plants tend to live in moist environments. Though the life of a nonvascular seedless plant is a cycle, this can be considered the initial step in the life cycle.
What consists of these five stages: prophase, prometaphase, metaphase, anaphase, and telophase?	meiosis	evolution	germination	mitosis	6.2 The Cell Cycle The cell cycle is an orderly sequence of events. Cells on the path to cell division proceed through a series of precisely timed and carefully regulated stages. In eukaryotes, the cell cycle consists of a long preparatory period, called interphase. Interphase is divided into G1, S, and G2 phases. Mitosis consists of five stages: prophase, prometaphase, metaphase, anaphase, and telophase. Mitosis is usually accompanied by cytokinesis, during which the cytoplasmic components of the daughter cells are separated either by an actin ring (animal cells) or by cell plate formation (plant cells). Each step of the cell cycle is monitored by internal controls called checkpoints. There are three major checkpoints in the cell cycle: one near the end of G1, a second at the G2–M transition, and the third during metaphase.
What is the name of the muscle at the end of the esophagus?	throat	neck	intestine	sphincter	From the pharynx, the food moves into the esophagus. The esophagus is a long, narrow tube that passes food from the pharynx to the stomach by peristalsis. The esophagus has no other digestive functions. At the end of the esophagus, a muscle called a sphincter controls the entrance to the stomach. The sphincter opens to let food into the stomach and then closes again to prevent food from passing back into the esophagus.
What do you call the high and low points of transverse waves?	bands and troughs	echos and troughs	waves and troughs	crests and troughs	In a transverse wave, such as a wave in a rope, the medium vibrates at right angles to the direction that the wave travels. The high points of transverse waves are called crests, and the low points are called troughs.
For each initial glucose molecules, two pyruvate molecules will enter where?	Golgi apparatus	the plasma	the nucleus	the mitochondria	Aerobic respiration begins with the entry of the product of glycolysis, pyruvate, into the mitochondria. For each initial glucose molecules, two pyruvate molecules will enter the mitochondria. Pyruvate, however, is not the molecule that enters the Krebs cycle. Prior to entry into this cycle, pyruvate must be converted into a 2-carbon acetyl-CoenzymeA (acetyl-CoA) unit. The conversion of pyruvate into acetyl-CoA is referred to as the pyruvate dehydrogenase reaction. It is catalyzed by the pyruvate dehydrogenase complex. This process produces one NADH electron carrier while releasing a CO 2 molecule. This step is also known as the link reaction or transition step, as it links glycolysis and the Krebs cycle. Of course, as two pyruvates result from glycolysis, two acetyl-CoAs are produced as are 2 NADH molecules.
Through which artery does blood enter the kidneys?	cerebral artery	thoracic artery	jugular	renal artery	Blood enters the kidney through the renal artery, which branches into capillaries. When blood passes through capillaries of the glomerulus of a nephron, blood pressure forces some of the water and dissolved substances in the blood to cross the capillary walls into Bowman’s capsule.
Where do radio waves lie on the electromagnetic spectrum?	top	middle	far right	far left	Courtesy of NASA. Radio waves lie at the far left of the electromagnetic spectrum . Public Domain.
What links the trophic levels from producers to top carnivores?	fuel chains	ecosystems	environments	food chains
The waste of cows releases a lot of which type of gas?	sulphur	carbon dioxide	oxygen	methane	Volatile organic compounds (VOCs) are carbon compounds such as methane. VOCs are released in many human activities, such as raising livestock. Livestock wastes produce a lot of methane.

During adolescence, what causes most of the changes associated with puberty?

methane

estrogen

nicotine

testosterone

During adolescence, testosterone causes most of the changes associated with puberty. It causes the reproductive organs to mature. It also causes other adult male traits to develop. For example, it causes the voice to deepen and facial hair to start growing.

What is essential for cellular respiration for all aerobic organisms?

carbon

nitrogen

water

oxygen

An online guide from the University of Illinois about air masses and fronts is found here: http://ww2010. atmos. uiuc. edu/%28Gh%29/guides/mtr/af/home. rxml .

Breeding in birds occurs through an internal type of what process?

stimulation

segmentation

sedimentation

fertilization

Breeding in birds is through internal fertilization, where the egg is fertilized inside the female.

In an endothermic reaction, what is absorbed by the reaction?

atoms

food

fuel

energy

Because energy is a product, energy is given off by the reaction. Therefore, this reaction is exothermic. Because energy is a reactant, energy is absorbed by the reaction. Therefore, this reaction is endothermic.

What scientist and monk is best known for his experiments with pea plants?

aristotle

steiner mendel

charles darwin

gregor mendel

Gregor Mendel was born in 1822 and grew up on his parents’ farm in Austria. He did well in school and became a monk. He also went to the University of Vienna, where he studied science and math. His professors encouraged him to learn science through experimentation and to use math to make sense of his results. Mendel is best known for his experiments with the pea plant Pisum sativum (see Figure below ). You can watch a video about Mendel and his research at the following link: http://www. metacafe. com/watch/hl-19246625/milestones_in_science_engineering_gregor_mendel_and_classical_genetics/ .

What are structures that protect the coast like barrier islands called?

fortresses

domes

dunes

breakwaters

Breakwaters are structures that protect the coast like barrier islands. Groins are structures that help prevent longshore drift from eroding a beach.

What leads to multiple copies of a chromosomal region?

subtractions

minimilizations

gene modification

duplications (or amplifications )

Duplications (or amplifications ) lead to multiple copies of a chromosomal region, increasing the number of the genes located within that region. Some genes may be duplicated in their entirety.

The larger surface area of leaves allows them to capture more what?

chlorophyll

pollen

molecules

sunlight

Roots: Support for the Plant Roots are not well preserved in the fossil record; nevertheless, it seems that they did appear later in evolution than vascular tissue. The development of an extensive network of roots represented a significant new feature of vascular plants. Thin rhizoids attached the bryophytes to the substrate. Their rather flimsy filaments did not provide a strong anchor for the plant; neither did they absorb water and nutrients. In contrast, roots, with their prominent vascular tissue system, transfer water and minerals from the soil to the rest of the plant. The extensive network of roots that penetrates deep in the ground to reach sources of water also stabilizes trees by acting as ballast and an anchor. The majority of roots establish a symbiotic relationship with fungi, forming mycorrhizae. In the mycorrhizae, fungal hyphae grow around the root and within the root around the cells, and in some instances within the cells. This benefits the plant by greatly increasing the surface area for absorption. Leaves, Sporophylls, and Strobili A third adaptation marks seedless vascular plants. Accompanying the prominence of the sporophyte and the development of vascular tissue, the appearance of true leaves improved photosynthetic efficiency. Leaves capture more sunlight with their increased surface area. In addition to photosynthesis, leaves play another role in the life of the plants. Pinecones, mature fronds of ferns, and flowers are all sporophylls—leaves that were modified structurally to bear sporangia. Strobili are structures that contain the sporangia. They are prominent in conifers and are known commonly as cones: for example, the pine cones of pine trees.

What is connected to, and dependent on, the gametophyte?

the zygote

the sperm

the chromosomes

the sporophyte

Following fertilization, the sporophyte forms. The sporophyte is connected to, and dependent on, the gametophyte.

After passing through capillaries and being filtered, clean blood leaves what organ through a vein?

heart

pancreas

liver

kidney

Blood with wastes enters each kidney through an artery, which branches into many capillaries. After passing through capillaries and being filtered, the clean blood leaves the kidney through a vein.

What kind of medical intervention seeks to eradicate diseases like polio and measles?

malnutrition

surgical intervention

nutrition

vaccination

The ostrich, kiwi, rhea, cassowary, and moa are examples of what kind of birds?

prehistoric

predators

raptors

flightless

Some birds have lost the ability to fly during the course of their evolution. Several flightless birds are shown in Figure below . They include the ostrich, kiwi, rhea, cassowary, and moa. All of these birds have long legs and are adapted for running. The penguins shown in the figure are also flightless birds, but they have a very different body shape. That’s because they are adapted for swimming rather than running.

What occurs when individuals of different species strive for a limited resource in the same area?

intraspecific competition

vegetal competition

asexual competition

interspecific competition

Interspecific competition happens when individuals of different species strive for a limited resource in the same area. Since any two species have different traits, one species will be able to out-compete the other. One species will be better adapted to its environment, and essentially "win" the competition. The other species will have lower reproductive success and lower population growth, resulting in a lower survival rate. For example, cheetahs and lions feed on similar prey. If prey is limited, then lions may catch more prey than cheetahs. This will force the cheetahs to either leave the area or suffer a decrease in population.

Most fungi reproduce asexually by producing what?

toxins

seeds

ions

spores

Almost all fungi reproduce asexually by producing spores. A fungi spore is a haploid cell produced by mitosis from a haploid parent cell. It is genetically identical to the parent cell. Fungi spores can develop into new haploid individuals without being fertilized.

Alchemists, as early as the eighth century, knew nitric acid as aqua fortis, which means?

applied water

isolated water

clean water

strong water

Nitrogen Oxyacids and Salts Nitrogen pentaoxide, N2O5, and NO2 react with water to form nitric acid, HNO3. Alchemists, as early as the eighth century, knew nitric acid (shown in Figure 18.50) as aqua fortis (meaning "strong water"). The acid was useful in the separation of gold from silver because it dissolves silver but not gold. Traces of nitric acid occur in the atmosphere after thunderstorms, and its salts are widely distributed in nature. There are tremendous deposits of Chile saltpeter,.

Particles of sand and what other substance are carried by longshore drift?

soil

magma

bone

rock

Longshore drift carries particles of sand and rock down a coastline.

Most reptiles reproduce sexually and have what type of fertilization?

mechanical

additional

external

internal

Most reptiles reproduce sexually and have internal fertilization.

What is type of substance is formed when water vapor condenses or when ice melts?

gaseous water

toxic water

chemical water

liquid water

Liquid water is formed when water vapor condenses (i. e. , H 2 O(g) → H 2 O(l) or when ice melts (i. e. , H 2 O(s) → H 2 O(l)). Because water is a molecular substance, it is a poor conductor of electricity in its pure form. However, as we will see later, its conductivity can be improved by the addition of certain substances. Water molecules are polar, and this overall polarity gives rise to many of the properties of water. For example, an interesting effect is seen when water is placed in a static electric field, as shown in the Figure below and the video below. This phenomenon can be explained in terms of the polarity of water molecules.

What occur because solid lithosphere travels on a round planet?

ejecta earthquakes

aeration earthquakes

volcanos

intraplate earthquakes

Intraplate earthquakes occur because solid lithosphere travels on a round planet.

What is the unit of evolution?

biome

species

community

population

Remember that individuals do not evolve. Their genes do not change over time. The unit of evolution is the population. A population consists of organisms of the same species that live in the same area. In terms of evolution, the population is assumed to be a relatively closed group. This means that most mating takes place within the population. The science that focuses on evolution within populations is population genetics . It is a combination of evolutionary theory and Mendelian genetics.

The boiling points of liquid also correlate to the strength of which forces?

gravitational

centrifugal

supramolecular

intermolecular

The boiling points of liquid also correlate to the strength of the intermolecular forces. Recall that diethyl ether has weak dispersion forces, which meant that the liquid has a high vapor pressure. The weak forces also mean that it does not require a large an input of energy to make diethyl ether boil and so it has a relatively low normal boiling point of 34.6°C. Water, with its much stronger hydrogen bonding, has a low vapor pressure and a higher normal boiling point of 100°C.

Vitamin d is made in the skin when it is exposed to what?

dirt

darkness

water

sunlight

Vitamins are organic compounds that the body needs in small amounts to function properly. Humans need 16 different vitamins. Six of them are listed in Table below . Vitamin D is made in the skin when it is exposed to sunlight. Bacteria that normally live in the gut make vitamins B12 and K. All other vitamins must come from food. The table shows good food sources of the vitamins.

Of the three basic types of radioactive emissions, what particle is the most penetrating?

beta

neutron

alpha

gamma

The various emissions will differ considerably in their ability to go through matter, known as their penetrating ability . The α-particle has the least penetrating power since it is the largest and slowest emission. It can be blocked by a sheet of paper or a human hand. Beta particles are more penetrating than alpha particles, but can be stopped by a thin sheet of aluminum. Of the three basic types of emissions, gamma particle are the most penetrating. A thick lead shield is required to stop gamma emissions. Positrons represent a special case in that they annihilate when they come in contact with electrons. The collision of a positron and an electron results in the formation of two gamma emissions that go 180 degrees away from each other.

Which ocean zone is the narrow strip along a coastline that is covered by water at high tide and exposed to air at low tide?

deep zone

miniscule zone

calcareous zone

intertidal zone

One of the most familiar ocean zones is the intertidal zone. This is the narrow strip along a coastline that is covered by water at high tide and exposed to air at low tide. You can see an example of an intertidal zone in Figure below . There are plenty of nutrients and sunlight in the intertidal zone. Producers here include phytoplankton and algae. Other organisms include barnacles, snails, crabs, and mussels. They must have adaptations for the constantly changing conditions in this zone.

Elongation is the addition of what to the mrna strand?

filaments

codons

glycine

nucleotides

Elongation is the addition of nucleotides to the mRNA strand.

What is the distance north or south of the equator called?

Prime Meridian

inclination

longitude

latitude

Latitude is the distance north or south of the equator. It’s measured in degrees, from 0° to 90°. Several climate factors vary with latitude.

The force exerted by a diving board is conservative, provided the internal friction is this?

significant

static

intrinsic

negligible

7.4 Conservative Forces and Potential Energy 9. What is a conservative force? 10. The force exerted by a diving board is conservative, provided the internal friction is negligible. Assuming friction is negligible, describe changes in the potential energy of a diving board as a swimmer dives from it, starting just before the swimmer steps on the board until just after his feet leave it. Define mechanical energy. What is the relationship of mechanical energy to nonconservative forces? What happens to mechanical energy if only conservative forces act? 12. What is the relationship of potential energy to conservative force?.

Along with other elements, most ores are made of what?

sodium

coal

crystals

metal

When the ore leaves the mine, it is not yet a useful material ( Figure below ). Most ores are a combination of metal and other elements. The rocks are full of valuable minerals. They also contain rock that isn't valuable, which is called waste rock. The valuable minerals must be separated from the waste rock.

The bottoms—but not the tops—of the wave slow down because of what?

temperature

size

vibration

friction

In shallow water close to shore, waves start to drag on the bottom of the water. The bottoms—but not the tops—of the wave slow down because of friction. This causes the waves to steepen until they break and fall over, carrying water onto the shore as surf.

Molecular geometry is the three-dimensional arrangement of atoms in a what?

nucleus

genes

DNA

molecule

Molecular geometry is the three-dimensional arrangement of atoms in a molecule. The molecular geometry, or shape, of a molecule is an important factor that affects the physical and chemical properties of a compound. Those properties include melting and boiling points, solubility, density, and the types of chemical reactions that a compound undergoes. In this lesson, you will learn a technique to predict molecular geometry based on a molecule’s Lewis electron dot structure.

What mineral is used to produce glass?

pyrite

lead

feldspar

quartz

Silver is used to make sterling silver jewelry. Table salt is the mineral halite. Glass is produced from the mineral quartz.

What is caused by atoms or ions when they share or transfer valance electrons?

force of repulsion

loss of charge

gain of charge

force of attraction

No, not all birds can fly. And not all birds have wings. This penguin is a good example. Their wings have evolved into flippers, adapted for swimming instead of flying. The kiwi of New Zealand is another bird without wings.

Due to the time it takes for light to reach us, galaxies at the edge of the universe are distant in terms of space and what else?

energy

gravity

temperature

time

The galaxies at the edge of the Universe are a great distance away. But they are something else that is distant. Because it takes so long for light from so far away to reach us, they are also very far back in time ( Figure below ).

Some membrane proteins that actively transport ions contribute to what?

cellular potential

organism potential

protein potential

membrane potential

In which human organ do the juveniles develop into sexually mature adults?

muscles

liver

tissues

intestines

Both sexes of sockeye salmon turn red with green heads just prior to what?

migrating

dying

feeding

spawning

Wild male and female Sockeye salmon before spawning. Sockeye salmon are blue tinged with silver in color while living in the ocean. Just prior to spawning, both sexes turn red with green heads. Sockeye spawn mostly in streams having lakes in their watershed. The young fish spend up to three years in the freshwater lake before migrating to the ocean. Migratory fish spend from one to four years in salt water, and thus are four to six years old when they return to spawn. Navigation to the home river is thought to be done using the characteristic smell of the stream, and possibly the sun.

While the numerical aperture can be used to compare resolutions of various objectives, it does not indicate how far the lens could be from the what?

focal point

microscope

diameter

specimen

While the numerical aperture can be used to compare resolutions of various objectives, it does not indicate how far the lens could be from the specimen. This is specified by the “working distance,” which is the distance (in mm usually) from the front lens element of the objective to the specimen, or cover glass. The higher the NA the closer the lens will be to the specimen and the more chances there are of breaking the cover slip and damaging both the specimen and the lens. The focal length of an objective lens is different than the working distance. This is because objective lenses are made of a combination of lenses and the focal length is measured from inside the barrel. The working distance is a parameter that microscopists can use more readily as it is measured from the outermost lens. The working distance decreases as the NA and magnification both increase.

Energy from the sun has a wide range of wavelengths.what is the total range of energy called?

thermal spectrum

heat spectrum

light spectrum

electromagnetic spectrum

Energy from the Sun has a wide range of wavelengths. The total range of energy is called the electromagnetic spectrum . You can see it in Figure below .

When something loses electrons, it must also?

gain protons

reduce protons

slow down

gain electrons

Solution The charges, as well as the atoms, must balance in reactions. The silver atom is being oxidized from the 0 oxidation state to the 1+ state. Whenever something loses electrons, something must also gain electrons (be reduced) to balance the equation. Oxygen is a good oxidizing agent for these reactions because it can gain electrons to go from the 0 oxidation state to the 2− state.

Water and chemical elements that organisms need keep recycling through biogeochemical what?

effects

mutations

levels

cycles

Water and chemical elements that organisms need keep recycling through biogeochemical cycles. These cycles include biotic and abiotic components of ecosystems.

What is the most abundant biochemical compound, making up the cell walls of plants?

mitochondria

magnesium

cytoplasm

cellulose

Cellulose is the most abundant biochemical compound. It makes up the cell walls of plants and gives support to trunks and stems. Cellulose also provides needed fiber in the human diet. We can’t digest cellulose, but it helps keep food wastes moving through the digestive tract.

What organisms use cilia, pseudopods, or flagella to move?

prokaryotes

bacteria

arthropods

protists

Protists use cilia, pseudopods, or flagella to move.

During which phase do sister chromatids separate and the centromeres divide?

passivation

cell phase

gap cycle

anaphase

During anaphase , sister chromatids separate and the centromeres divide. The sister chromatids are pulled apart by the shortening of the spindle fibers. This is like reeling in a fish by shortening the fishing line. One sister chromatid moves to one pole of the cell, and the other sister chromatid moves to the opposite pole. At the end of anaphase, each pole of the cell has a complete set of chromosomes.

What term describes a type of redox reaction in which the same substance is both oxidized and reduced?

misappropriation

interposition

disapprobation

disproportion

Disproportion is a type of redox reaction in which the same substance is both oxidized and reduced. Identify the element that is disproportionating and indicate the initial and final oxidation numbers of that element. 2CuCl(aq) → CuCl2(aq) + Cu(s) Saylor URL: http://www. saylor. org/books.

Each organism inherits one of what item for each gene from each parent?

cell

molecule

phenotype

allele

What term is used to refer to the external female reproductive structures collectively?

uterus

cervix

vagina

vulva

External Female Genitals The external female reproductive structures are referred to collectively as the vulva (Figure 27.10). The mons pubis is a pad of fat that is located at the anterior, over the pubic bone. After puberty, it becomes covered in pubic hair. The labia majora (labia = “lips”; majora = “larger”) are folds of hair-covered skin that begin just posterior to the mons pubis. The thinner and more pigmented labia minora (labia = “lips”; minora = “smaller”) extend medial to the labia majora. Although they naturally vary in shape and size from woman to woman, the labia minora serve to protect the female urethra and the entrance to the female reproductive tract. The superior, anterior portions of the labia minora come together to encircle the clitoris (or glans clitoris), an organ that originates from the same cells as the glans penis and has abundant nerves that make it important in sexual sensation and orgasm. The hymen is a thin membrane that sometimes partially covers the entrance to the vagina. An intact hymen cannot be used as an indication of “virginity”; even at birth, this is only a partial membrane, as menstrual fluid and other secretions must be able to exit the body, regardless of penile–vaginal intercourse. The vaginal opening is located between the opening of the urethra and the anus. It is flanked by outlets to the Bartholin’s glands (or greater vestibular glands).

Which state of matter has the lowest density?

solids

liquids

fluids

gases

Gases have much lower densities than liquids and solids. For example, liquid water is over 1000 times more dense than water vapor at STP.

Skeletal, cardiac, and smooth are the three types of what cells and possess morphologies correlated with their functions?

bone

cartilage tissue

organ

muscle

4.4 Muscle Tissue and Motion The three types of muscle cells are skeletal, cardiac, and smooth. Their morphologies match their specific functions in the body. Skeletal muscle is voluntary and responds to conscious stimuli. The cells are striated and multinucleated appearing as long, unbranched cylinders. Cardiac muscle is involuntary and found only in the heart. Each cell is striated with a single nucleus and they attach to one another to form long fibers. Cells are attached to one another at intercalated disks. The cells are interconnected physically and electrochemically to act as a syncytium. Cardiac muscle cells contract autonomously and involuntarily. Smooth muscle is involuntary. Each cell is a spindle-shaped fiber and contains a single nucleus. No striations are evident because the actin and myosin filaments do not align in the cytoplasm.

What do glands in the skin produce to cool down the body?

mucus

lactic acid

saliva

sweat

glands in the skin that produce sweat, a salty fluid that helps cool down the body.

The only obvious difference between boys and girls at birth is what type of organs?

nervous

digestive

respiratory

reproductive

The only obvious difference between boys and girls at birth is their reproductive organs. However, even the reproductive organs start out the same in both sexes.

Mammals have a number of kinds of thermoreceptors, each specific for a particular what?

weight range

electrical range

oxygen range

temperature range

With a shape that specially suits its function of sending nerve signals to other cells, the human nerve cell is an example of what?

evolution

adaptation

maturation

specialization

The human nerve cell in Figure below is a good example of a specialized animal cell. Its shape suits it for its function of sending nerve signals to other cells. A nerve cell couldn’t take this shape if it were surrounded by a rigid cell wall.

What is defined as the mass per unit volume of a substance?

height

weight

diameter

density

As you know, density is defined as the mass per unit volume of a substance. Since gases all occupy the same volume on a per mole basis, the density of a particular gas is dependent on its molar mass. A gas with a small molar mass will have a lower density than a gas with a large molar mass. Gas densities are typically reported in g/L. Gas density can be calculated from molar mass and molar volume.

What reaction means, literally, “splitting with water"?

fission

aqueous

hydroxis

hydrolysis

Esters are neutral compounds, unlike the acids from which they are formed. In typical reactions, the alkoxy (OR′) group of an ester is replaced by another group. One such reaction is hydrolysis, literally “splitting with water. ” The hydrolysis of esters is catalyzed by either an acid or a base. Acidic hydrolysis is simply the reverse of esterification. The ester is heated with a large excess of water containing a strong-acid catalyst. Like esterification, the reaction is reversible and does not go to completion.

Approximately how much larger is the radius of an atom than that of its nucleus?

100 times

1 times

1000 times

10 times

The radius of an atom is approximately 10 times larger than the radius of its nucleus. If the radius of the nucleus were 1.0 cm, what would be the radius of the atom in centimeters? in miles?.

What can be worn to protect hands and skin from harm?

filters

splints

masks

gloves

What type of movements are produced when the angle between the bones of a joint changes?

oblong

microscopic

circular

angular

The wide range of movement allowed by synovial joints produces different types of movements. Angular movements are produced when the angle between the bones of a joint changes. Flexion, or bending, occurs when the angle between the bones decreases. Moving the forearm upward at the elbow is an example of flexion. Extension is the opposite of flexion in that the angle between the bones of a joint increases. Rotational movement is the movement of a bone as it rotates around its own longitudinal axis. Movement of the head as in saying “no” is an example of rotation.

What senses the movement of liquid in ear canals?

muscle cells

Ear Drum

Brain Cells

hair cells

This bottle of water models the semicircular canals in your ears. When you tip the bottle, the water moves up or down the sides of the bottle; when you tip your head, the liquid inside the semicircular canals moves up and down the sides of the canals. Tiny hair cells lining the canals sense the movement of liquid and send messages to the brain.

What part of the brain regulates certain hormones associated with reproduction during breeding seasons?

hippocampus

thalamus

frontal lobe

hypothalamus

What is any nonmetallic, inorganic solid that is strong enough for use in structural applications called?

glass

tissue

metallic

ceramic

Ceramics A ceramic is any nonmetallic, inorganic solid that is strong enough for use in structural applications. Traditional ceramics, which are based on metal silicates or aluminosilicates, are the materials used to make pottery, china, bricks, and concrete. Modern ceramics contain a much wider range of components and can be classified as either ceramic oxides, which are based on metal oxides such as alumina (Al2O3), zirconia (ZrO2), and beryllia (BeO), or nonoxide ceramics, which are based on metal carbides such as silicon carbide (carborundum, SiC) and tungsten carbide (WC), or nitrides like silicon nitride (Si 3N4) and boron nitride (BN). All modern ceramics are hard, lightweight, and stable at very high temperatures. Unfortunately, however, they are also rather brittle, tending to crack or break under stresses that would cause metals to bend or dent. Thus a major challenge for materials scientists is to take advantage of the desirable properties of ceramics, such as their thermal and oxidative stability, chemical inertness, and toughness, while finding ways to decrease their brittleness to use them in new applications. Few metals can be used in jet engines, for example, because most lose mechanical strength and react with oxygen at the very high operating.

What is the outer layer of the sun made up of?

gas

oxygen

nitrogen

plasma

outermost layer of the sun, made up of a plasma that extends millions of kilometers into space.

Viruses may damage or kill cells by causing the release of hydrolytic enzymes from where?

glands

capillaries

lipids

lysosomes

Species that have diverged from their common ancestors have greater differences in what?

immunology

life span

cell structure

dna sequence

Evidence from the fossil record can be combined with data from molecular clocks. A molecular clock uses DNA sequences (or the proteins they encode) to estimate relatedness among species. Molecular clocks estimate the time in geologic history when related species diverged from a common ancestor. Molecular clocks are based on the assumption that mutations accumulate through time at a steady average rate for a given region of DNA. Species that have accumulated greater differences in their DNA sequences are assumed to have diverged from their common ancestor in the more distant past. Molecular clocks based on different regions of DNA may be used together for more accuracy.

In a fuel cell, energy is not stored; electrical energy is provided by what?

consumption reaction

fusion reaction

carbon reaction

chemical reaction

called an alkaline battery when adapted to operate under alkaline conditions. Button batteries have a high output-to-mass ratio; lithium–iodine batteries consist of a solid electrolyte; the nickel– cadmium (NiCad) battery is rechargeable; and the lead–acid battery, which is also rechargeable, does not require the electrodes to be in separate compartments. A fuel cell requires an external supply of reactants as the products of the reaction are continuously removed. In a fuel cell, energy is not stored; electrical energy is provided by a chemical reaction.

What substance comes toward earth's crust through mantle plumes?

gas

rocks

water

magma

Some volcanoes form over active hot spots . Scientists count about 50 hot spots on the Earth. Hot spots may be in the middle of a tectonic plate. Hot spots lie directly above a column of hot rock called a mantle plume . Mantle plumes continuously bring magma up from the mantle towards the crust ( Figure below ).

A plant is composed of two main types of tissue: meristematic tissue and what other kind of tissue?

nonvascular tissue

synovial tissue

muscle tissue

permanent tissue

CHAPTER SUMMARY 30.1 The Plant Body A vascular plant consists of two organ systems: the shoot system and the root system. The shoot system includes the aboveground vegetative portions (stems and leaves) and reproductive parts (flowers and fruits). The root system supports the plant and is usually underground. A plant is composed of two main types of tissue: meristematic tissue and permanent tissue. Meristematic tissue consists of actively dividing cells found in root and shoot tips. As growth occurs, meristematic tissue differentiates into permanent tissue, which is categorized as either simple or complex. Simple tissues are made up of similar cell types; examples include dermal tissue and ground tissue. Dermal tissue provides the outer covering of the plant. Ground tissue is responsible for photosynthesis; it also supports vascular tissue and may store water and sugars. Complex tissues are made up of different cell types. Vascular tissue, for example, is made up of xylem and phloem cells.

The smallest and lightest alcohols (methanol, ethanol, propanol) are completely soluble in?

argon

gasoline

oil

water

The smallest and lightest alcohols (methanol, ethanol, propanol) are completely soluble in water in all proportions. In a solution, the hydroxyl groups of alcohol molecules and the water molecules form hydrogen bonds with each other, resulting in complete miscibility. However, as the length of the carbon chain increases, the solubility decreases. The solubility of 1-butanol is 7.4 g per 100 g of water, while that of 1-pentanol is 2.7 g per 100 g water, and 1-octanol is 0.06 g per 100 g water. The carbon chain portion of the larger alcohol molecule is nonpolar and leads to the decreased solubility of the overall compound.

In which stage do chromosomes line up one on top of each other along the middle of the cell, similar to how they line up in mitosis?

chromosome ii

hectase ii

cyclohexane ii

metaphase ii

Metaphase II: The chromosomes line up one on top of each other along the middle of the cell, similar to how they line up in mitosis. The spindle is attached to the centromere of each chromosome.

If the frequency of the electromagnetic wave is the same as the natural frequencies of the system, the transfer of what is much more efficient?

light

heat

sound

energy

24.4 Energy in Electromagnetic Waves Anyone who has used a microwave oven knows there is energy in electromagnetic waves. Sometimes this energy is obvious, such as in the warmth of the summer sun. Other times it is subtle, such as the unfelt energy of gamma rays, which can destroy living cells. Electromagnetic waves can bring energy into a system by virtue of their electric and magnetic fields. These fields can exert forces and move charges in the system and, thus, do work on them. If the frequency of the electromagnetic wave is the same as the natural frequencies of the system (such as microwaves at the resonant frequency of water molecules), the transfer of energy is much more efficient. Connections: Waves and Particles The behavior of electromagnetic radiation clearly exhibits wave characteristics. But we shall find in later modules that at high frequencies, electromagnetic radiation also exhibits particle characteristics. These particle characteristics will be used to explain more of the properties of the electromagnetic spectrum and to introduce the formal study of modern physics. Another startling discovery of modern physics is that particles, such as electrons and protons, exhibit wave characteristics. This simultaneous sharing of wave and particle properties for all submicroscopic entities is one of the great symmetries in nature.

When are nutrients absorbed into the body?

after digestion

after excretion

before digestion

during digestion

What happens to the length of the days in the fall?

they get longer

they stay the same

they change randomly

they get shorter

For example, in the fall, when the days start to get shorter, the trees sense that there is less sunlight. The plant is stimulated, and it sends messages telling the leaves to change colors and fall. This is an example of photoperiodism , the reaction of organisms, such as plants, to the length of day or night. Photoperiodism is also the reaction of plants to the length of light and dark periods. Many flowering plants sense the length of night, a dark period, as a signal to flower. Each plant has a different photoperiod, or night length. When the plant senses the appropriate length of darkness, resulting in an appropriate length of daylight, it flowers. Flowering plants are classified as long-day plants or short-day plants. Long-day plants flower when the length of daylight exceeds the necessary photoperiod, and short-day plants flower when the day length is shorter than the necessary photoperiod. Long-day plants include carnations, clover, lettuce, wheat, and turnips. Short-day plants include cotton, rice, and sugar cane.

Of the nine classes of vertebrates, how many are fish?

three

one

four

five

Of course. But what type? Of the nine classes of vertebrates, five are fish. Each of the five classes has distinguishing characteristics that allow members to be classified appropriately. Stingray are cartilaginous fish, related to sharks.

After fertilization is complete, no other sperm can enter. the fertilized ovule forms the seed, whereas the tissues of the ovary become this?

vegetables

plant

wheat

fruit

events in angiosperms are known as double fertilization (Figure 32.18). After fertilization is complete, no other sperm can enter. The fertilized ovule forms the seed, whereas the tissues of the ovary become the fruit, usually enveloping the seed.

What is a fluid-filled body cavity that is completely enclosed by mesoderm called?

choroid

pseudocoelom

hymenium

coelom

Later, a true coelom evolved. This is a fluid-filled body cavity that is completely enclosed by mesoderm. The coelom lies between the digestive cavity and body wall. You can see it in the invertebrate in Figure below . Modern invertebrates with a coelom include mollusks (Phylum Mollusca) and annelids (Phylum Annelida).

Which is the least massive outer planet?

jupiter

venus

mars

uranus

Uranus is the least massive outer planet. Its mass is only about 14 times the mass of Earth. Like all of the outer planets, Uranus is much less dense than Earth. Gravity is actually weaker than on Earth’s surface. If you were at the top of the clouds on Uranus, you would weigh about 10 percent less than what you weigh on Earth.

The nervous system is characterized by electrical signals that are sent from one area to another. whether those areas are close or very far apart, the signal must travel along this?

tendons

axial

hairs

axon

12.4 The Action Potential The nervous system is characterized by electrical signals that are sent from one area to another. Whether those areas are close or very far apart, the signal must travel along an axon. The basis of the electrical signal is the controlled distribution of ions across the membrane. Transmembrane ion channels regulate when ions can move in or out of the cell, so that a precise signal is generated. This signal is the action potential which has a very characteristic shape based on voltage changes across the membrane in a given time period. The membrane is normally at rest with established Na+ and K+ concentrations on either side. A stimulus will start the depolarization of the membrane, and voltage-gated channels will result in further depolarization followed by repolarization of the membrane. A slight overshoot of hyperpolarization marks the end of the action potential. While an action potential is in progress, another cannot be generated under the same conditions. While the voltage-gated Na+ channel is inactivated, absolutely no action potentials can be generated. Once that channel has returned to its resting state, a new action potential is possible, but it must be started by a relatively stronger stimulus to overcome the K + leaving the cell. The action potential travels down the axon as voltage-gated ion channels are opened by the spreading depolarization. In unmyelinated axons, this happens in a continuous fashion because there are voltage-gated channels throughout the membrane. In myelinated axons, propagation is described as saltatory because voltage-gated channels are only found at the nodes of Ranvier and the electrical events seem to “jump” from one node to the next. Saltatory conduction is faster than continuous conduction, meaning that myelinated axons propagate their signals faster. The diameter of the axon also makes a difference as ions diffusing within the cell have less resistance in a wider space.

What occurs when light reflects off a very smooth surface and forms a clear image?

refraction

projection

absorption

regular reflection

Regular reflection occurs when light reflects off a very smooth surface and forms a clear image. Diffuse reflection occurs when light reflects off a rough surface and forms a blurry image or no image at all.

The head of the sperm contains what, which holds the chromosomes?

eggs

nerve cells

fiber

nucleus

The head of the sperm contains the nucleus. The nucleus holds the chromosomes. In humans, the nucleus of a sperm cell contains 23 chromosomes. The acrosome on the head contains enzymes that help the sperm penetrate an egg.

What system is responsible for defending your body against sickness?

digestion system

nervous system

circulatory system

immune system

Infectious diseases are diseases that spread from person to person. They are caused by pathogens such as bacteria, viruses or fungi. What can you do to avoid infectious diseases? Eating right and getting plenty of sleep are a good start. These habits will help keep your immune system healthy. With a healthy immune system, you will be able to fight off many pathogens. The next best way is to avoid pathogens. Though this is difficult, there are steps you can take to limit your exposure to pathogens.

What effect occurs when a few individuals start, or found, a new population?

pioneer

divergent

convergent

founder

Founder effect occurs when a few individuals start, or found, a new population. By chance, allele frequencies of the founders may be different from allele frequencies of the population they left. An example is described in the Figure below .

Each kidney is supplied by a renal artery and what else?

coronary artery

spinal cord

brain vein

renal vein

Each kidney is supplied by a renal artery and renal vein.

What cell structures capture light energy from the sun and use it with water and carbon dioxide to produce sugars for food?

nuclei

fibroblasts

ribosomes

chloroplasts

Chloroplasts capture light energy from the sun and use it with water and carbon dioxide to produce sugars for food. Chloroplasts look like flat discs and are usually 2 to 10 micrometers in diameter and 1 micrometer thick. A model of a chloroplast is shown in Figure below . The chloroplast is enclosed by an inner and an outer phospholipid membrane. Between these two layers is the intermembrane space. The fluid within the chloroplast is called the stroma , and it contains one or more molecules of small, circular DNA. The stroma also has ribosomes. Within the stroma are stacks of thylakoids , sub-organelles that are the site of photosynthesis. The thylakoids are arranged in stacks called grana (singular: granum). A thylakoid has a flattened disk shape. Inside it is an empty area called the thylakoid space or lumen. Photosynthesis takes place on the thylakoid membrane.

What is released when catabolic pathways break down complex molecules?

food

hydrogen

oxygen

energy

Mass and volume are examples of what kind of properties?

varied properties

dynamic properties

exclusive properties

extensive properties

Mass and volume are examples of extensive properties.

What technique is used by insects and birds to find food, mates, and safety from predators?

mating

playing

sleeping

flying

Other than insects, virtually no other animals can inhabit the airy world. Flying is a sure-fire way to escape from all but the quickest nonflying predators. Flying also gives birds a good view for finding food and mates.

What property of food is determined by burning the food and measuring the heat released?

additives

acidity

nutrients

calories

Food calories are determined by burning the food and measuring the heat released.

What simple machine works with a wheel and axle in a wheelbarrow?

blade

pulley

hammer

lever

Look at the wheelbarrow in the Figure below . It is used to carry heavy objects. It consists of two simple machines: a lever and a wheel and axle. Effort is applied to the lever by picking up the handles of the wheelbarrow. The lever, in turn, applies upward force to the load. The force is increased by the lever, making the load easier to lift. Effort is applied to the wheel of the wheelbarrow by pushing it over the ground. The rolling wheel turns the axle and increases the force, making it easier to push the load.

What type of joint has the greatest range of motion?

Pivot

Hinge

Gliding

ball-and-socket

There are a variety of types of movable joints, which are illustrated in Figure below . The joints are classified by how they move. For example, a ball-and-socket joint, such as the shoulder, has the greatest range of motion, allowing movement in several directions. Other movable joints, including hinge joints such as the knee, allow less movement.

What is the movement of molecules from an area of high concentration of the molecules to an area with a lower concentration?

secretion

absorption

condensation

diffusion

Diffusion is the movement of molecules from an area of high concentration of the molecules to an area with a lower concentration. The difference in the concentrations of the molecules in the two areas is called the concentration gradient . Diffusion will continue until this gradient has been eliminated. Since diffusion moves materials from an area of higher concentration to the lower, it is described as moving solutes "down the concentration gradient. " The end result of diffusion is an equal concentration, or equilibrium , of molecules on both sides of the membrane.

Light-weight air-filled bones and a large four-chambered heart helps a bird do what?

run

swim

digest

fly

Bird organ systems are adapted for flight. For example, they have light-weight air-filled bones and a large four-chambered heart.

The myod protein deserves its designation as a master regulatory what?

enzyme

hormone

protein

gene

Some organisms can reproduce sexually or asexually. Under what conditions might each type of reproduction be an advantage?.

When flagellated sperm must swim to the egg, sexual reproduction requires the presence of what substance?

sunshine

air

nitrogen

water

The male gametophyte produces flagellated sperm that must swim to the egg formed by the female gametophyte. For this reason, sexual reproduction must happen in the presence of water. Therefore, nonvascular plants tend to live in moist environments. Though the life of a nonvascular seedless plant is a cycle, this can be considered the initial step in the life cycle.

What consists of these five stages: prophase, prometaphase, metaphase, anaphase, and telophase?

meiosis

evolution

germination

mitosis

6.2 The Cell Cycle The cell cycle is an orderly sequence of events. Cells on the path to cell division proceed through a series of precisely timed and carefully regulated stages. In eukaryotes, the cell cycle consists of a long preparatory period, called interphase. Interphase is divided into G1, S, and G2 phases. Mitosis consists of five stages: prophase, prometaphase, metaphase, anaphase, and telophase. Mitosis is usually accompanied by cytokinesis, during which the cytoplasmic components of the daughter cells are separated either by an actin ring (animal cells) or by cell plate formation (plant cells). Each step of the cell cycle is monitored by internal controls called checkpoints. There are three major checkpoints in the cell cycle: one near the end of G1, a second at the G2–M transition, and the third during metaphase.

What is the name of the muscle at the end of the esophagus?

throat

neck

intestine

sphincter

From the pharynx, the food moves into the esophagus. The esophagus is a long, narrow tube that passes food from the pharynx to the stomach by peristalsis. The esophagus has no other digestive functions. At the end of the esophagus, a muscle called a sphincter controls the entrance to the stomach. The sphincter opens to let food into the stomach and then closes again to prevent food from passing back into the esophagus.

What do you call the high and low points of transverse waves?

bands and troughs

echos and troughs

waves and troughs

crests and troughs

In a transverse wave, such as a wave in a rope, the medium vibrates at right angles to the direction that the wave travels. The high points of transverse waves are called crests, and the low points are called troughs.

For each initial glucose molecules, two pyruvate molecules will enter where?

Golgi apparatus

the plasma

the nucleus

the mitochondria

Aerobic respiration begins with the entry of the product of glycolysis, pyruvate, into the mitochondria. For each initial glucose molecules, two pyruvate molecules will enter the mitochondria. Pyruvate, however, is not the molecule that enters the Krebs cycle. Prior to entry into this cycle, pyruvate must be converted into a 2-carbon acetyl-CoenzymeA (acetyl-CoA) unit. The conversion of pyruvate into acetyl-CoA is referred to as the pyruvate dehydrogenase reaction. It is catalyzed by the pyruvate dehydrogenase complex. This process produces one NADH electron carrier while releasing a CO 2 molecule. This step is also known as the link reaction or transition step, as it links glycolysis and the Krebs cycle. Of course, as two pyruvates result from glycolysis, two acetyl-CoAs are produced as are 2 NADH molecules.

Through which artery does blood enter the kidneys?

cerebral artery

thoracic artery

jugular

renal artery

Blood enters the kidney through the renal artery, which branches into capillaries. When blood passes through capillaries of the glomerulus of a nephron, blood pressure forces some of the water and dissolved substances in the blood to cross the capillary walls into Bowman’s capsule.

Where do radio waves lie on the electromagnetic spectrum?

top

middle

far right

far left

Courtesy of NASA. Radio waves lie at the far left of the electromagnetic spectrum . Public Domain.

What links the trophic levels from producers to top carnivores?

fuel chains

ecosystems

environments

food chains

The waste of cows releases a lot of which type of gas?

sulphur

carbon dioxide

oxygen

methane

Volatile organic compounds (VOCs) are carbon compounds such as methane. VOCs are released in many human activities, such as raising livestock. Livestock wastes produce a lot of methane.