allenai/sciq · Datasets at Hugging Face

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What is a controlled scientific test that often takes place in a lab?	an observeration	a testing	a viewing	an experiment	An experiment is a controlled scientific test that often takes place in a lab. It investigates the effects of an independent variable on a dependent variable.
What causes the endometrium to thicken during a menstrual cycle?	ovulation	testosterone	blood	estradiol	Hormone levels during the follicular phase, ovulation, and the luteal phase are compared. During the follicular phase, LH and FSH secreted from the pituitary stimulate several follicles to grow. The follicles produce low levels of estradiol that inhibit GnRH secretion by the hypothalamus, keeping LH and FSH levels low. Low levels of estradiol also cause the endometrial arteries to constrict, resulting in menstruation. During the time leading up to ovulation, LH and FSH stimulate maturation of one of the follicles. The growing follicle begins to produce high levels of estradiol, which stimulates GnRH secretion by the hypothalamus. As a result, LH and FSH levels rise, resulting in ovulation about a day later. Estradiol also causes the endometrium to thicken. After ovulation, the ovarian cycle enters the luteal phase. LH from the pituitary stimulates growth of the corpus luteum from the ruptured follicle. The corpus luteum secretes estradiol and progesterone that block GnRH production by the hypothalamus and LH and FSH production by the pituitary. Estradiol and progesterone also cause the endometrium to further develop. Figure 43.15 The ovarian and menstrual cycles of female reproduction are regulated by hormones produced by the hypothalamus, pituitary, and ovaries.
What process refers to the conversion of atmospheric nitrogen to ammonia?	biological respiratory fixation	biological nutrient fixation	biological ammonia fixation	biological nitrogen fixation	31.3 Nutritional Adaptations of Plants Atmospheric nitrogen is the largest pool of available nitrogen in terrestrial ecosystems. However, plants cannot use this nitrogen because they do not have the necessary enzymes. Biological nitrogen fixation (BNF) is the conversion of atmospheric nitrogen to ammonia. The most important source of BNF is the symbiotic interaction between soil bacteria and legumes. The bacteria form nodules on the legume’s roots in which nitrogen fixation takes place. Fungi form symbiotic associations (mycorrhizae) with plants, becoming integrated into the physical structure of the root. Through mycorrhization, the plant obtains minerals from the soil and the fungus obtains photosynthate from the plant root. Ectomycorrhizae form an extensive dense sheath around the root, while endomycorrhizae are embedded within the root tissue. Some plants—parasites, saprophytes, symbionts, epiphytes, and insectivores—have evolved adaptations to obtain their organic or mineral nutrition from various sources.
What is it called when two species evolve matching traits?	spontaneous mutation	Allopatric speciation	interconnection	coevolution	Two species may often interact with each other and have a close relationship. Examples include flowers and the animals that pollinate them. When one of the two species evolves new traits, the other species may evolve matching traits. This is called coevolution . You can see an example of this in Figure below . The very long beak of this hummingbird co-evolved with the tubular flowers it pollinates. Only this species of hummingbird can reach nectar deep in the flowers.
What is the term for water that falls from clouds?	wind	lightning	atmosphere	precipitation	Precipitation is water that falls from clouds. It may fall as liquid or frozen water. Types of frozen precipitation include snow, sleet, freezing rain, and hail.
Echinoderms lack what type of system that in humans consists of the brain and spinal cord?	peripheral nervous system	autonomic system	endocrine system	centralized nervous system	Echinoderms lack respiratory and excretory systems. Instead, the thin walls of their tube feet allow oxygen to diffuse in and wastes to diffuse out. Echinoderms also lack a centralized nervous system. They have an open circulatory system and lack a heart. On the other hand, echinoderms have a well-developed coelom and a complete digestive system. Echinoderms use pheromones to communicate with each other. They detect the chemicals with sensory cells on their body surface. Some echinoderms also have simple eyes ( ocelli ) that can sense light. Like annelids, echinoderms have the ability to regenerate a missing body part.
What class of invertebrate animals has additional appendages called the chelicerae and the pedipalps?	mammals	fish	arthropod	arachnid	Arachnids also have two additional pairs of appendages. The first pair, the chelicerae , serve in feeding and defense. The next pair, the pedipalps , help the organisms feed, move, and reproduce.
The burning of what type of fuels is a major source of sulfur oxides and nitrogen oxides?	synthetic	biofuels	renewable	fossil
What is the science of classifying living things is called?	physiology	entomology	methodology	taxonomy	Scientists classify living things to make sense of biodiversity and who how living things are related. The science of classifying living things is called taxonomy.
What is it called when your joints start to wear out and they become stiff and painful?	tendonitis	adenitis	endometriosis	arthritis	During late adulthood, people are not as physically able. For example, they usually have less muscle and slower reflexes. Their immune system also doesn’t work as well as it used to. As a result, they have a harder time fighting diseases like the flu. The risk of developing diseases such as heart disease and cancer continues to rise. Arthritis is also common. In arthritis, joints wear out and become stiff and painful. As many as one in four late adults may develop Alzheimer’s disease. In this disease, brain changes cause mental abilities to decrease.
Gas, liquid, and solid describe what property of matter?	Quatitative	Chemical	Physical	states	In addition to these properties, other physical properties of matter include the state of matter. States of matter include liquid, solid, and gaseous states. For example at 20°C, coal exists as a solid and water exists as a liquid. Additional examples of physical properties include:.
Differences in fitness among different members of a population can lead to what kind of selection?	origin selection	fluid selection	subliminal selection	natural selection	Natural selection occurs when there are differences in fitness among members of a population.
What cells carry oxygen?	lymph cells	marrow cells	white blood cells	red blood cells	Red blood cells carry oxygen, white blood cells defend the body, and platelets help blood clot.
What coenzyme is used in the transfer of energy in muscles?	glycogen	carbolic acid	hydrofluoric acid	atp or adenozine triphosphate
Which asexual reproduction method do starfish use to reproduce?	budding	fission	spawning	fragmentation	Starfish reproduce by fragmentation and yeasts reproduce by budding. Both are types of asexual reproduction.
What enables gamma rays to pass through hard matters like bones, teeth, and just about anything?	Density	Weight	Being Heavier	their extremely high energy	The extremely high energy of gamma rays allows them to penetrate just about anything. They can even pass through bones and teeth. This makes gamma rays very dangerous. They can destroy living cells, produce gene mutations, and cause cancer. Ironically, the deadly effects of gamma rays can be used to treat cancer. In this type of treatment, a medical device sends out focused gamma rays that target cancerous cells. The gamma rays kill the cells and destroy the cancer.
What type of mammals includes opossums, kangaroos, and koalas?	monotremes	crustaceans	arthropods	marsupials
What do we call animals that have a backbone and belong to the phylum chordata?	invertebrates	organelles	mammals	vertebrates	Vertebrates are animals that have a backbone. All of them are placed in the Phylum Chordata. Modern vertebrates include fish, amphibians, reptiles, birds, and mammals. Only about 5 percent of animal species are vertebrates.
Living organisms are affected by changes in ph which can include basic conditions and what other kinds of conditions?	complex	carbolic	sodium	acidic	3.3 Acidic and basic conditions affect living organisms.
What makes up most of the interior of a plant?	transport tissue	conjunction tissue	support tissue	ground tissue	Ground tissue makes up most of the interior of a plant. It carries out basic metabolic functions and stores food and water.
What part of a plant, which is attached to its stem nodes, is the "main organ" of photosynthesis?	spores	flowers	roots	leaves
Experiments have shown that acceleration is exactly inversely proportional to mass, just as it is exactly linearly proportional to what?	kinetic energy	net internal force	speed	net external force	where m is the mass of the system. Experiments have shown that acceleration is exactly inversely proportional to mass, just as it is exactly linearly proportional to the net external force.
What term describes a disease in which the immune system attacks the body’s own cells?	acute	contagious	inflammatory	autoimmune	An autoimmune disease is a disease in which the immune system attacks the body’s own cells. Why this happens is not known for certain, but a combination of genetic and environmental factors are likely to be responsible. Type 1 diabetes is an example of an autoimmune disease. In this case, the immune system attacks cells of the pancreas. Two other examples are multiple sclerosis and rheumatoid arthritis.
Flow of what can introduce alleles that are advantageous or ones that are disadvantageous?	larvae	babies	eggs	genes
A life cycle continues through reproduction and what?	example	response	mechanical	development
Bacteria are like eukaryotic cells in that they have cytoplasm, ribosomes, and a?	brain	cell wall	chloroplast	plasma membrane	Bacteria are like eukaryotic cells in that they have cytoplasm, ribosomes, and a plasma membrane.
When zinc metal is mixed with sulfur and heated, what is produced?	iron	extraction sulfide	methane sulfide	zinc sulfide	In the course of a chemical reaction between a metal and a nonmetal, electrons are transferred from the metal atoms to the nonmetal atoms. For example, when zinc metal is mixed with sulfur and heated, the compound zinc sulfide is produced. Two valence electrons from each zinc atom are transferred to each sulfur atom.
What cage composed of 12 pairs of ribs, with their costal cartilages and the sternum, protects the heart and lungs?	cervical	sacral	lumbar	thoracic	7.4 The Thoracic Cage The thoracic cage protects the heart and lungs. It is composed of 12 pairs of ribs with their costal cartilages and the sternum. The ribs are anchored posteriorly to the 12 thoracic vertebrae. The sternum consists of the manubrium, body, and xiphoid process. The manubrium and body are joined at the sternal angle, which is also the site for attachment of the second ribs. Ribs are flattened, curved bones and are numbered 1–12. Posteriorly, the head of the rib articulates with the costal facets located on the bodies of thoracic vertebrae and the rib tubercle articulates with the facet located on the vertebral transverse process. The angle of the ribs forms the most posterior portion of the thoracic cage. The costal groove in the inferior margin of each rib carries blood vessels and a nerve. Anteriorly, each rib ends in a costal cartilage. True ribs (1–7) attach directly to the sternum via their costal cartilage. The false ribs (8–12) either attach to the sternum indirectly or not at all. Ribs 8–10 have their costal cartilages attached to the cartilage of the next higher rib. The floating ribs (11–12) are short and do not attach to the sternum or to another rib.
What is the ability of an atom to emit charged particles and energy from its nucleus called?	power	accumulation	conductivity	radioactivity	Radioactivity is the ability of an atom to emit charged particles and energy from its nucleus. The charged particles and energy are called by the general term radiation.
Diffusion is an effective transport mechanism over the spatial scales typically found at what level?	atom	electromagnetic	molecular	cellular
In a car race on a circular track, where the start and finish line are the same, what quantity is neglible?	total distance	total acceleration	partial displacement	total displacement	To return to the first image, these cars travel a distance of 500 miles over the course of the race. However, they are traveling in a circle, and the start and finish line are the same. Therefore, when the car finishes the race, it is in essentially the same position it was when it started. The car's total displacement is only a few feet.
What is another name for molecular compounds?	synthetic compounds	phenotype compounds	oxidized compounds	covalent compounds	The physical state and properties of a particular compound depend in large part on the type of chemical bonding it displays. Molecular compounds , sometimes called covalent compounds, display a wide range of physical properties due to the different types of intermolecular attractions such as different kinds of polar interactions. The melting and boiling points of molecular compounds are generally quite low compared to those of ionic compounds . This is because the energy required to disrupt the intermolecular forces between molecules is far less than the energy required to break the ionic bonds in a crystalline ionic compound. Since molecular compounds are composed of neutral molecules, their electrical conductivity is generally quite poor, whether in the solid or liquid state. Ionic compounds do not conduct electricity in the solid state because of their rigid structure, but conduct well when either molten or dissolved into a solution. The water solubility of molecular compounds is variable and depends primarily on the type of intermolecular forces involved. Substances that exhibit hydrogen bonding or dipole-dipole forces are generally water soluble, whereas those that exhibit only London dispersion forces are generally insoluble. Most, but not all, ionic compounds are quite soluble in water. Table below summarizes some of the differences between ionic and molecular compounds.
The long mouth-tube that some insects use to suck up the nectar of the flower is called what?	pistil	stamen	prosthesis	proboscis	Some insects use siphoning, as if sucking through a straw, like moths and butterflies. This long mouth-tube that they use to suck up the nectar of the flower is called a proboscis . Some moths, however, have no mouthparts at all. Some insects obtain food by sponging , like the housefly. Sponging means that the mouthpart can absorb liquid food and send it to the esophagus. The housefly is able to eat solid food by releasing saliva and dabbing it over the food. As the saliva dissolves the food, the sponging mouthpart absorbs the liquid food.
Cnvs result from regions of what being duplicated or deleted inconsistently within the population?	DNA	genes	cytoplasm	genome
Insects can have specialized mouthparts, such as a proboscis, to siphon the nectar from what?	fruits	stems	shrubs	flowers	Insects can have specialized mouthparts, such as a proboscis, to siphon the nectar from a flower.
What is the invisible force that pulls things to earth?	electromagnetism	motion	momentum	gravity	Gravity cannot be seen. It does not require things to touch. Gravity is an invisible force. Many things are pulled to the Earth by gravity. Can you think of some things that fall toward the Earth?.
What do we call the seasonal movement of animals?	immigration	population	trade	migration	Monarch butterflies gather in large groups as they migrate 2,500 miles south each fall. They return to the north in the spring. This migration is a cycle that repeats every year.
What kind of beneficial relationships with other organisms are common in the plant kingdom?	autotrophic	symbiotic	Host	mutualistic
Some marine algae have evolved special structures capable of what plant process?	seed germination	pollination	respiration	photosynthesis	in color. Golden algae are found in both freshwater and marine environments, where they form a major part of the plankton community. The brown algae are primarily marine, multicellular organisms that are known colloquially as seaweeds. Giant kelps are a type of brown algae. Some brown algae have evolved specialized tissues that resemble terrestrial plants, with root-like holdfasts, stem-like stipes, and leaf-like blades that are capable of photosynthesis. The stipes of giant kelps are enormous, extending in some cases for 60 meters. A variety of algal life cycles exists, but the most complex is alternation of generations, in which both haploid and diploid stages involve multicellularity. Compare this life cycle to that of humans, for instance. Haploid gametes produced by meiosis (sperm and egg) combine in fertilization to generate a diploid zygote that undergoes many rounds of mitosis to produce a multicellular embryo and then a fetus. However, the individual sperm and egg themselves never become multicellular beings. Terrestrial plants also have evolved alternation of generations. In the brown algae genus Laminaria, haploid spores develop into multicellular gametophytes, which produce haploid gametes that combine to produce diploid organisms that then become multicellular organisms with a different structure from the haploid form (Figure 23.19). Certain other organisms perform alternation of generations in which both the haploid and diploid forms look the same.
What is the substance called whenatoms of different elements join together?	plants	crusts	crystals	compounds	Did you ever make cupcakes from scratch? You mix together flour, sugar, eggs, and other ingredients to make the batter, put the batter into cupcake papers, and then put them into the oven to bake. The cupcakes that come out of the oven after baking are different from any of the individual ingredients that went into the batter. Like the ingredients that join together to make cupcakes, atoms of different elements can join together to form entirely different substances called compounds. In cupcakes, the eggs and other wet ingredients cause the dry ingredients to stick together. What causes elements to stick together in compounds? The answer is chemical bonds.
What type of solid has atoms arranged in a repeating pattern?	hydrocarbons	ions	metals	crystals	Some solids are not crystals. Glass, or the rock obsidian, are solid. However, they are not crystals. In a crystal , the atoms are arranged in a pattern. This pattern is regular and it repeats. The image below shows how the atoms are arranged in halite (table salt) ( Figure below ). Halite contains atoms of sodium and chlorine in a pattern. Notice that the pattern goes in all three dimensions.
What is the process called when secretory cells export products?	morphogenesis	endocytosis	isolation	exocytosis
Natural resources that are limited in supply and cannot be replaced except over millions of years are known as what?	renewable	precious	biological	nonrenewable	Nonrenewable resources are natural resources that are limited in supply and cannot be replaced except over millions of years. Nonrenewable energy resources include fossil fuels and radioactive elements such as uranium.
What is a hydrocarbon in which the carbon chain joins to itself in a ring?	acid hydrocarbon	asymmetrical hydrocarbon	circular hydrocarbon	cyclic hydrocarbon	A cyclic hydrocarbon is a hydrocarbon in which the carbon chain joins to itself in a ring. A cycloalkane is a cyclic hydrocarbon in which all of the carbon-carbon bonds are single bonds. Like other alkanes, cycloalkanes are saturated compounds. Cycloalkanes have the general formula of C n H 2n . The simplest cycloalkane is cyclopropane, a three-carbon ring.
The first photosynthetic organisms were not plants, but types of what that lived in the water?	algae	pathogens	fungi	bacteria	The first photosynthetic organisms were bacteria that lived in the water. So, where did plants come from? Evidence shows that plants evolved from freshwater green algae, a protist ( Figure below ). The similarities between green algae and plants is one piece of evidence. They both have cellulose in their cell walls, and they share many of the same chemicals that give them color. So what separates green algae from green plants?.
What is the second stage of photosynthesis?	glucose destruction	pigment release	production of protein	production of glucose	The second stage of photosynthesis is the production of glucose from carbon dioxide. This process occurs in a continuous cycle, named after its discover, Melvin Calvin. The Calvin cycle uses CO 2 and the energy temporarily stored in ATP and NADPH to make the sugar glucose.
Which layer is the lithosphere located?	nearest layer	eclipses layer	radii layer	outermost layer	Lithosphere and asthenosphere are layers based on physical properties. The outermost layer is the lithosphere . The lithosphere is the crust and the uppermost mantle. In terms of physical properties, this layer is rigid, solid, and brittle. It is easily cracked or broken.
What is speed at any given instant called?	relative speed	spontaneous speed	marginal speed	instantaneous speed	Speed may be constant, but often it varies from moment to moment. Speed at any given instant is called instantaneous speed. It is much more difficult to calculate than average speed.
During birth, a baby passes from the uterus through what organ to leave the body?	Esophagus	Ovary	the urethra	the vagina	The vagina is a cylinder-shaped organ that opens to the outside of the body. The other end joins with the uterus. Sperm deposited in the vagina swim up through the cervix, into the uterus, and from there into a fallopian tube. During birth, a baby passes from the uterus through the vagina to leave the body.
What type of earthquake creates a tsunami?	volcanic	Tectonic	collapse	underwater	An underwater earthquake creates a tsunami this way: the movement of the crust displaces water. The displacement forms a set of waves. The waves travel at jet speed through the ocean. Since the waves have low amplitudes and long wavelengths, they are unnoticed in deep water. As the waves reach shore they compress. They are also pushed upward by the shore. For these reasons, tsunamis can grow to enormous wave heights. Tsunami waves can cause tremendous destruction and loss of life. Fortunately, few undersea earthquakes generate tsunamis.
What is the smallest of the galilean moons?	aura	phoebe	demos	europa	Scientists think that Europa is a good place to look for extraterrestrial life. Europa is the smallest of the Galilean moons. The moon's surface is a smooth layer of ice. Scientists think that the ice may sit on top of an ocean of liquid water. How could Europa have liquid water when it is so far from the Sun? Europa is heated by Jupiter. Jupiter's tidal forces are so great that they stretch and squash its moon. This could produce enough heat for there to be liquid water. Numerous missions have been planned to explore Europa, including plans to drill through the ice and send a probe into the ocean. However, no such mission has yet been attempted.
What is the term for a combination of substances in which there is no chemical reaction?	a solution	a combination	a solute	a mixture	Like a chemical compound, a mixture consists of more than one chemical substance. Unlike a compound, a mixture does not have a fixed chemical composition. The substances in a mixture can be combined in any proportions. A mixture also does not involve a chemical reaction. Therefore, the substances in a mixture are not changed into unique new substances, and they can be separated from each other without a chemical reaction.
Where does the majority of chemical digestion occur?	large intestine	stomach	mouth	small intestine	Chemical digestion occurs when large food molecules are broken down into smaller nutrient molecules. This is a chemical process that begins in the mouth and stomach but occurs mainly in the small intestine.
The vertebrate endoskeleton includes a vertebral column, cranium, limbs, and what else?	blood girdles	tissue girdles	Skin Girdles	limb girdles	Vertebrate Endoskeletons. The vertebrate endoskeleton includes a vertebral column, cranium, limbs, and limb girdles. Can you find these parts in each endoskeleton shown here?.
What is defined as the velocity of the object at a given moment?	inertia	specific gravity	relativistic velocity	instantaneous velocity	The instantaneous velocity of an object is the velocity of the object at a given moment. If the object is moving with constant velocity, then the instantaneous velocity at every moment, the average velocity, and the constant velocity are all the same.
What is the term for an expression showing the relationship of the reaction rate to the concentrations of each reactant?	concentric law	decay law	flow law	rate law	The proportionality between the rate and becomes an equal sign by the insertion of a constant . A rate law is an expression showing the relationship of the reaction rate to the concentrations of each reactant. The specific rate constant is the proportionality constant relating the rate of the reaction to the concentrations of reactants. The rate law and the specific rate constant for any chemical reaction must be determined experimentally. The value of the rate constant is temperature dependent. A large value of the rate constant means that the reaction is relatively fast, while a small value of the rate constant means that the reaction is relatively slow.
How many pi bonds are found in a triple bond?	four	10	six	two	From the stirrup, the vibrations pass to the oval window . This is another membrane like the eardrum.
What is formed when an acidic solution and a basic solution react together in a neutralization reaction?	shallow	Sodium	seawater	salt	An acidic solution and a basic solution react together in a neutralization reaction that also forms a salt.
What is the causative agent of sleeping sickness in humans?	bacillus aerophilus	pseudomonas asplenii	escherichia coli	trypanosoma brucei	Figure 15.12 Trypanosoma brucei is the causative agent of sleeping sickness in humans. The mRNAs of this pathogen must be modified by the addition of nucleotides before protein synthesis can occur. (credit: modification of work by Torsten Ochsenreiter).
Living things that use energy to make food, both for themselves and other living things, are what part of an ecosystem?	growers	consumers	decomposers	producers	Producers are living things that use energy to make food. Producers make food for themselves and other living things. There are two types of producers:.
In science, what process produces evidence that helps answer questions and solve problems?	suspension	information	manipulation	investigation	Investigation is at the heart of science. It is how scientists do research. Scientific investigations produce evidence that helps answer questions and solve problems. If the evidence cannot provide answers or solutions, it may still be useful. It may lead to new questions or problems for investigation. As more knowledge is discovered, science advances.
What cellular structure is used during endocytosis to allow molecules to enter the cell?	membranes	nucleus	tissues	vesicles
What are unique about prokaryotic cells' organelles?	only membrane - bound	no cell walls	no epidermis	not membrane-bound	Diagram of a typical prokaryotic cell. Among other things, prokaryotic cells have a plasma membrane, cytoplasm, ribosomes, and DNA. Prokaryotes do not have membrane-bound organelles or a cell nucleus.
How long ago did the ancestors of mammals evolve?	100 million	10 million	50,900 million years	300 million years	Ancestors of mammals evolved close to 300 million years ago. They were amniotes called synapsids. Figure below shows how modern mammals evolved from synapsids. The stages of evolution from synapsids to mammals are described below.
A d. melanogaster population has an average heterozygosity of what?	22 %	19 %	21 %	14%
Traits that are affected by more than one gene are what type of traits?	dominant	monogenetic	recessive	polygenic traits	Traits that are affected by more than one gene are called polygenic traits . The genes that affect a polygenic trait may be closely linked on a chromosome, unlinked on a chromosome, or on different chromosomes. Polygenic traits are often difficult for geneticists to track because the polygenic trait may have many alleles. Also, independent assortment ensures the genes combine differently in gametes. Therefore, many different intermediate phenotypes exist in offspring. Eye color ( Figure below ), and skin color are examples of polygenic traits in humans.
Pharmacist and surveyor are two career options based in what type of science?	visible	obvious	Business	physical	There are many career options in physical science. Examples include pharmacist and surveyor.
What is another term for foodborne illness?	cancer	pathogen	disease	food poisoning	Harmful bacteria can enter your digestive system in food and make you sick. This is called foodborne illness or food poisoning. The bacteria, or the toxins they produce, may cause vomiting or cramping, in addition to the symptoms mentioned above. Foodborne illnesses can also be caused by viruses and parasites. The most common foodborne illnesses happen within a few minutes to a few hours, and make you feel really sick, but last for only about a day or so. Others can take longer for the illness to appear. Some people believe that the taste of food will tell you if it is bad. As a rule, you probably should not eat bad tasting food, but many contaminated foods can still taste good.
The mechanical advantage of a machine is related to how it changes what?	example	pressure	nature	force	The mechanical advantage of a machine is related to how it changes force. Explain this relationship.
What term in physics refers to the use of force to move an object?	velocity	mass	momentum	work	Work is defined differently in physics than in everyday language. In physics, work means the use of force to move an object. The teen who is playing tennis in Figure above is using force to move her tennis racket, so she is doing work. The teen who is studying isn’t moving anything, so she is not doing work.
What is the name of the organelle that helps make and transport proteins and lipids?	mitochondria	plasma membrane	nucleus	endoplasmic reticulum	The endoplasmic reticulum (ER) is an organelle that helps make and transport proteins and lipids. It’s made of folded membranes. Bits of membrane can pinch off to form tiny sacs called vesicles. The vesicles carry proteins or lipids away from the ER.
What machine is used to determine the calories in food, as well as the average heat yield from burning various grades of coal and oil?	alethiometer	radio telescope	thermometer	calorimeter	Though not particularly beautiful machines, calorimeters are incredibly useful ones. They are used to determine the calories (food energy) in food, as well as the average heat yield from burning various grades of coal and oil. The price of coal is often dependent on the heat yield from samples burned in a calorimeter.
What is the name of the outer part of the adrenal gland located above the kidneys?	spleen	nucleus	mitochondria	cortex	The two adrenal glands are located above the kidneys. Each gland has an inner and outer part. The outer part, called the cortex, secretes hormones such as cortisol, which helps the body deal with stress, and aldosterone, which helps regulate the balance of minerals in the body. The inner part of each adrenal gland, called the medulla, secretes fight-or-flight hormones such as adrenaline, which prepare the body to respond to emergencies. For example, adrenaline increases the amount of oxygen and glucose going to the muscles. You can see an animation of this response at the link below.
What kind of energy used heat from magma within the earth to heat homes or produce steam that turns turbines?	renewable energy	thermal energy	robust energy	geothermal energy	Geothermal energy uses heat from magma within the Earth to heat homes or produce steam that turns turbines.
The primary output of the basal nuclei is to the thalamus, which relays that output to where?	suffering cortex	effect cortex	Back cortex	cerebral cortex	Thalamus The thalamus is a collection of nuclei that relay information between the cerebral cortex and the periphery, spinal cord, or brain stem. All sensory information, except for the sense of smell, passes through the thalamus before processing by the cortex. Axons from the peripheral sensory organs, or intermediate nuclei, synapse in the thalamus, and thalamic neurons project directly to the cerebrum. It is a requisite synapse in any sensory pathway, except for olfaction. The thalamus does not just pass the information on, it also processes that information. For example, the portion of the thalamus that receives visual information will influence what visual stimuli are important, or what receives attention. The cerebrum also sends information down to the thalamus, which usually communicates motor commands. This involves interactions with the cerebellum and other nuclei in the brain stem. The cerebrum interacts with the basal nuclei, which involves connections with the thalamus. The primary output of the basal nuclei is to the thalamus, which relays that output to the cerebral cortex. The cortex also sends information to the thalamus that will then influence the effects of the basal nuclei.
The central nervous system is composed of the brain and what else?	the lateral cord	the sclerotic cord	the dynamic cord	the spinal cord	User:Grm_wnr/Wikimedia Commons, modified by CK-12 Foundation. The central nervous system is composed of the brain and the spinal cord . Public Domain.
A group of genetically identical individuals is called what?	a man	brother	replicant	a clone
Where on the earth's surface does the water cycle takes place?	inside,under,above	on , below , and below	for , above , and below	on, above, and below	The water cycle takes place on, above, and below Earth’s surface. In the cycle, water occurs as water vapor, liquid water, and ice. Many processes are involved as water changes state in the cycle. The atmosphere is an exchange pool for water. Ice masses, aquifers, and the deep ocean are water reservoirs.
Under which conditions do many bacteria carry out alcohol fermentation?	photosynthesis	melting	enzymatic	anaerobic
Fermat's principle states that what will always take the path that takes the least amount of time?	electricity	sound	wind	light	Light is a wave of changing electric and magnetic fields. Light waves are caused by disturbances in an electromagnetic field, like the acceleration of charged particles (such as electrons). Light has a dual nature; at times, it acts like waves, while at other times it acts like particles, called photons . Light travels through space at the maximum speed allowed by the laws of physics, called the speed of light. Light has no mass, but it carries energy and momentum. Fermat's principle states that light will always take the path that takes the least amount of time (not distance).
What trend is occurring involving the extent of arctic sea ice in summer?	Ice growth	slow decrease	water decrease	rapid decrease	The extent of Arctic sea ice in summer has been decreasing rapidly. The ice pictured below is the sea ice minimum in 2011 ( Figure below ). The yellow line is the median minimum ice extent for 1979–2000.
In vertebrates, cholesterol is synthesized in which organ and obtained from the diet?	heart	the bone	the brain	the liver
What is a group of lions called?	bevy	coven	herd	pride	Lions live in social groups called prides . Adult females in the pride hunt cooperatively, which is more efficient than hunting alone. Then they share the food with the rest of the pride. For their part, adult males defend the pride’s territory from other predators.
Which layer is found below the lithosphere?	stratosphere	troposphere	magnetosphere	asthenosphere	The asthenosphere is below the lithosphere. The asthenosphere is also in the upper mantle. This layer is solid, but it can flow and bend. A solid that can flow is like silly putty.
What is the name for the nonliving parts of ecosystems?	Dead factors	diverse factors	nucleic factors	abiotic factors	Abiotic factors are the nonliving parts of ecosystems. They include air, sunlight, soil, water, and minerals. These are all things that are needed for life. They determine which living things — and how many of them — an ecosystem can support. Figure below shows an ecosystem and its abiotic factors.
What do you call the electrons in the outermost energy level of an atom?	Proper electrons	Inner electrons	shell electrons	valence electrons	Electrons in the outermost energy level of an atom are called valence electrons. They determine many of the properties of an atom, including how reactive it is.
What are some of the giant fairy rings produced by?	sporangia	fronds	algae	mycelia
What are ingrowths on arthropod exoskeletons to which muscles attach?	rods	joints	pores	apodemes	Figure 33.3 Apodemes are ingrowths on arthropod exoskeletons to which muscles attach. The apodemes on this crab leg are located above and below the fulcrum of the claw. Contraction of muscles attached to the apodemes pulls the claw closed.
Which type of electrons plays the most important role in chemical reactions?	transition	noncovalent	intermediate	valence	Electron Configurations and the Periodic Table As described earlier, the periodic table arranges atoms based on increasing atomic number so that elements with the same chemical properties recur periodically. When their electron configurations are added to the table (Figure 6.30), we also see a periodic recurrence of similar electron configurations in the outer shells of these elements. Because they are in the outer shells of an atom, valence electrons play the most important role in chemical reactions. The outer electrons have the highest energy of the electrons in an atom and are most easily lost or shared than the core electrons. Valence electrons are also the determining factor in some physical properties of the elements. Elements in any one group (or column) have the same number of valence electrons; the alkali metals lithium and sodium each have only one valence electron, the alkaline earth metals beryllium and magnesium each have two, and the halogens fluorine and chlorine each have seven valence electrons. The similarity in chemical properties among.
What level is greater than 7 in a basic solution?	uh	fh	gh	ph	The solution is basic and so its pH is greater than 7. The reported pH is rounded to two decimal places because the original mass and volume has two significant figures.
What happens to volume as the temperature increases?	volume is unchanged	volume fluctuates	volume decreases	volume increases	The volume increases as the temperature increases. The result has three significant figures.
What does an array of radio telescopes collect?	microwaves	thermal waves	light waves	radio waves	Radio telescopes collect radio waves and are sometimes used in large arrays.
What kind of compounds contain positively and negatively charged ions in a ratio that results in an overall charge of zero?	zeronic ions	neutral compounds	zero charged compunds	ionic compounds	Summary The atoms in chemical compounds are held together by attractive electrostatic interactions known as chemical bonds. Ionic compounds contain positively and negatively charged ions in a ratio that results in an overall charge of zero. The ions are held together in a regular spatial arrangement by electrostatic forces. Mostcovalent compounds consist of molecules, groups of atoms in which one or more pairs of electrons are shared by at least two atoms to form a covalent bond. The atoms in molecules are held together by the electrostatic attractionbetween the positively charged nuclei of the bonded atoms and the negatively charged electrons shared by the nuclei. The molecular formula of a covalent compound gives the types and numbers of atoms present. Compounds that contain predominantly carbon and hydrogen are called organic compounds, whereas compounds that consist primarily of elements other than carbon and hydrogen areinorganic compounds. Diatomic molecules contain two atoms, andpolyatomic molecules contain more than two. A structural formula indicates the composition and approximate structure and shape of a molecule. Single bonds, double bonds, and triple bonds are covalent bonds in which one, two, and three pairs of electrons, respectively, are shared between two Saylor URL: http://www. saylor. org/books.
What are formed when crystals precipitate out from a liquid?	gaseous sedimentary rocks	diamonds	additive sedimentary rocks	chemical sedimentary rocks	Chemical sedimentary rocks form when crystals precipitate out from a liquid. The mineral halite, also called rock salt, forms this way. You can make halite! Leave a shallow dish of salt water out in the Sun. As the water evaporates, salt crystals form in the dish. There are other chemical sedimentary rocks, like gypsum ( Figure below ).
Roundworms exemplify what type of organization, where two or more types of tissues work together to perform a particular function as an organ?	delicate - level organization	bone-level organization	land-level organization	organ-level organization	Roundworms have organ-level organization, in which two or more types of tissues work together to perform a particular function as an organ. For example, a roundworm has a primitive brain that controls how the organism responds to the environment.
Where are protons and neutrons located?	epidermis	radius	electron shell	nucleus	Unlike protons and neutrons, which are located inside the nucleus at the center of the atom, electrons are found outside the nucleus. Because opposite electric charges attract each other, negative electrons are attracted to the positive nucleus. This force of attraction keeps electrons constantly moving through the otherwise empty space around the nucleus. The Figure below is a common way to represent the structure of an atom. It shows the electron as a particle orbiting the nucleus, similar to the way that planets orbit the sun.
Why do hummingbirds have long narrow bills?	for protection against predators	to feed their offspring	to store food	to reach the nectar at the bottom of flowers	dome-shaped plug of thick lava that cools near the vent of a volcano.
Bivalvia and gastropoda are classes of what phylum?	diatoms	Insects	fishes	mollusks	Which of the following statements about the anatomy of a mollusk is false? a. Mollusks have a radula for scraping food. Mollusks have ventral nerve cords. The tissue beneath the shell is called the mantle. The mantle cavity contains hemolymph. Mollusk Diversity This phylum is comprised of seven classes: Aplacophora, Monoplacophora, Polyplacophora, Bivalvia, Gastropoda, Cephalopoda, and Scaphopoda. Class Aplacophora (“bearing no plates”) includes worm-like animals living mostly on deep ocean bottoms. These animals lack a shell but have aragonite spicules on their skin. Members of class Monoplacophora (“bearing one plate”) have a single, cap-like shell enclosing the body. The monoplacophorans were believed extinct and only known as fossils until the discovery of Neopilina galatheae in 1952. Today, scientists have identified nearly two dozen living species. Animals in the class Polyplacophora (“bearing many plates”) are commonly known as “chitons” and bear an armor-like, eight-plated shell (Figure 15.25). These animals have a broad, ventral foot that is adapted for attachment to rocks and a mantle that extends beyond the shell in the form of a girdle. They breathe with ctenidia (gills) present ventrally. These animals have a radula modified for scraping. A single pair of nephridia for excretion is present.
Kinetic energy of moving particles of matter, measured by their temperatures are known as:	solar energy	visible energy	atmospheric energy	thermal energy	Heat is the transfer of thermal energy between substances. Thermal energy is the kinetic energy of moving particles of matter, measured by their temperature. Thermal energy always moves from matter with greater thermal energy to matter with less thermal energy, so it moves from warmer to cooler substances. You can see this in the Figure below . Faster-moving particles of the warmer substance bump into and transfer some of their energy to slower-moving particles of the cooler substance. Thermal energy is transferred in this way until both substances have the same thermal energy and temperature. For a visual introduction to these concepts, watch the animation “Temperature vs. Heat” at this URL:.
What is the term for a process that changes some chemical substances into others?	chain reaction	acid reaction	toxic reaction	chemical reaction	A chemical reaction is a process that changes some chemical substances into others. During a chemical reaction, the reactants are used up to create the products.

What is a controlled scientific test that often takes place in a lab?

an observeration

a testing

a viewing

an experiment

An experiment is a controlled scientific test that often takes place in a lab. It investigates the effects of an independent variable on a dependent variable.

What causes the endometrium to thicken during a menstrual cycle?

ovulation

testosterone

blood

estradiol

Hormone levels during the follicular phase, ovulation, and the luteal phase are compared. During the follicular phase, LH and FSH secreted from the pituitary stimulate several follicles to grow. The follicles produce low levels of estradiol that inhibit GnRH secretion by the hypothalamus, keeping LH and FSH levels low. Low levels of estradiol also cause the endometrial arteries to constrict, resulting in menstruation. During the time leading up to ovulation, LH and FSH stimulate maturation of one of the follicles. The growing follicle begins to produce high levels of estradiol, which stimulates GnRH secretion by the hypothalamus. As a result, LH and FSH levels rise, resulting in ovulation about a day later. Estradiol also causes the endometrium to thicken. After ovulation, the ovarian cycle enters the luteal phase. LH from the pituitary stimulates growth of the corpus luteum from the ruptured follicle. The corpus luteum secretes estradiol and progesterone that block GnRH production by the hypothalamus and LH and FSH production by the pituitary. Estradiol and progesterone also cause the endometrium to further develop. Figure 43.15 The ovarian and menstrual cycles of female reproduction are regulated by hormones produced by the hypothalamus, pituitary, and ovaries.

What process refers to the conversion of atmospheric nitrogen to ammonia?

biological respiratory fixation

biological nutrient fixation

biological ammonia fixation

biological nitrogen fixation

31.3 Nutritional Adaptations of Plants Atmospheric nitrogen is the largest pool of available nitrogen in terrestrial ecosystems. However, plants cannot use this nitrogen because they do not have the necessary enzymes. Biological nitrogen fixation (BNF) is the conversion of atmospheric nitrogen to ammonia. The most important source of BNF is the symbiotic interaction between soil bacteria and legumes. The bacteria form nodules on the legume’s roots in which nitrogen fixation takes place. Fungi form symbiotic associations (mycorrhizae) with plants, becoming integrated into the physical structure of the root. Through mycorrhization, the plant obtains minerals from the soil and the fungus obtains photosynthate from the plant root. Ectomycorrhizae form an extensive dense sheath around the root, while endomycorrhizae are embedded within the root tissue. Some plants—parasites, saprophytes, symbionts, epiphytes, and insectivores—have evolved adaptations to obtain their organic or mineral nutrition from various sources.

What is it called when two species evolve matching traits?

spontaneous mutation

Allopatric speciation

interconnection

coevolution

Two species may often interact with each other and have a close relationship. Examples include flowers and the animals that pollinate them. When one of the two species evolves new traits, the other species may evolve matching traits. This is called coevolution . You can see an example of this in Figure below . The very long beak of this hummingbird co-evolved with the tubular flowers it pollinates. Only this species of hummingbird can reach nectar deep in the flowers.

What is the term for water that falls from clouds?

wind

lightning

atmosphere

precipitation

Precipitation is water that falls from clouds. It may fall as liquid or frozen water. Types of frozen precipitation include snow, sleet, freezing rain, and hail.

Echinoderms lack what type of system that in humans consists of the brain and spinal cord?

peripheral nervous system

autonomic system

endocrine system

centralized nervous system

Echinoderms lack respiratory and excretory systems. Instead, the thin walls of their tube feet allow oxygen to diffuse in and wastes to diffuse out. Echinoderms also lack a centralized nervous system. They have an open circulatory system and lack a heart. On the other hand, echinoderms have a well-developed coelom and a complete digestive system. Echinoderms use pheromones to communicate with each other. They detect the chemicals with sensory cells on their body surface. Some echinoderms also have simple eyes ( ocelli ) that can sense light. Like annelids, echinoderms have the ability to regenerate a missing body part.

What class of invertebrate animals has additional appendages called the chelicerae and the pedipalps?

mammals

fish

arthropod

arachnid

Arachnids also have two additional pairs of appendages. The first pair, the chelicerae , serve in feeding and defense. The next pair, the pedipalps , help the organisms feed, move, and reproduce.

The burning of what type of fuels is a major source of sulfur oxides and nitrogen oxides?

synthetic

biofuels

renewable

fossil

What is the science of classifying living things is called?

physiology

entomology

methodology

taxonomy

Scientists classify living things to make sense of biodiversity and who how living things are related. The science of classifying living things is called taxonomy.

What is it called when your joints start to wear out and they become stiff and painful?

tendonitis

adenitis

endometriosis

arthritis

During late adulthood, people are not as physically able. For example, they usually have less muscle and slower reflexes. Their immune system also doesn’t work as well as it used to. As a result, they have a harder time fighting diseases like the flu. The risk of developing diseases such as heart disease and cancer continues to rise. Arthritis is also common. In arthritis, joints wear out and become stiff and painful. As many as one in four late adults may develop Alzheimer’s disease. In this disease, brain changes cause mental abilities to decrease.

Gas, liquid, and solid describe what property of matter?

Quatitative

Chemical

Physical

states

In addition to these properties, other physical properties of matter include the state of matter. States of matter include liquid, solid, and gaseous states. For example at 20°C, coal exists as a solid and water exists as a liquid. Additional examples of physical properties include:.

Differences in fitness among different members of a population can lead to what kind of selection?

origin selection

fluid selection

subliminal selection

natural selection

Natural selection occurs when there are differences in fitness among members of a population.

What cells carry oxygen?

lymph cells

marrow cells

white blood cells

red blood cells

Red blood cells carry oxygen, white blood cells defend the body, and platelets help blood clot.

What coenzyme is used in the transfer of energy in muscles?

glycogen

carbolic acid

hydrofluoric acid

atp or adenozine triphosphate

Which asexual reproduction method do starfish use to reproduce?

budding

fission

spawning

fragmentation

Starfish reproduce by fragmentation and yeasts reproduce by budding. Both are types of asexual reproduction.

What enables gamma rays to pass through hard matters like bones, teeth, and just about anything?

Density

Weight

Being Heavier

their extremely high energy

The extremely high energy of gamma rays allows them to penetrate just about anything. They can even pass through bones and teeth. This makes gamma rays very dangerous. They can destroy living cells, produce gene mutations, and cause cancer. Ironically, the deadly effects of gamma rays can be used to treat cancer. In this type of treatment, a medical device sends out focused gamma rays that target cancerous cells. The gamma rays kill the cells and destroy the cancer.

What type of mammals includes opossums, kangaroos, and koalas?

monotremes

crustaceans

arthropods

marsupials

What do we call animals that have a backbone and belong to the phylum chordata?

invertebrates

organelles

mammals

vertebrates

Vertebrates are animals that have a backbone. All of them are placed in the Phylum Chordata. Modern vertebrates include fish, amphibians, reptiles, birds, and mammals. Only about 5 percent of animal species are vertebrates.

Living organisms are affected by changes in ph which can include basic conditions and what other kinds of conditions?

complex

carbolic

sodium

acidic

3.3 Acidic and basic conditions affect living organisms.

What makes up most of the interior of a plant?

transport tissue

conjunction tissue

support tissue

ground tissue

Ground tissue makes up most of the interior of a plant. It carries out basic metabolic functions and stores food and water.

What part of a plant, which is attached to its stem nodes, is the "main organ" of photosynthesis?

spores

flowers

roots

leaves

Experiments have shown that acceleration is exactly inversely proportional to mass, just as it is exactly linearly proportional to what?

kinetic energy

net internal force

speed

net external force

where m is the mass of the system. Experiments have shown that acceleration is exactly inversely proportional to mass, just as it is exactly linearly proportional to the net external force.

What term describes a disease in which the immune system attacks the body’s own cells?

acute

contagious

inflammatory

autoimmune

An autoimmune disease is a disease in which the immune system attacks the body’s own cells. Why this happens is not known for certain, but a combination of genetic and environmental factors are likely to be responsible. Type 1 diabetes is an example of an autoimmune disease. In this case, the immune system attacks cells of the pancreas. Two other examples are multiple sclerosis and rheumatoid arthritis.

Flow of what can introduce alleles that are advantageous or ones that are disadvantageous?

larvae

babies

eggs

genes

A life cycle continues through reproduction and what?

example

response

mechanical

development

Bacteria are like eukaryotic cells in that they have cytoplasm, ribosomes, and a?

brain

cell wall

chloroplast

plasma membrane

Bacteria are like eukaryotic cells in that they have cytoplasm, ribosomes, and a plasma membrane.

When zinc metal is mixed with sulfur and heated, what is produced?

iron

extraction sulfide

methane sulfide

zinc sulfide

In the course of a chemical reaction between a metal and a nonmetal, electrons are transferred from the metal atoms to the nonmetal atoms. For example, when zinc metal is mixed with sulfur and heated, the compound zinc sulfide is produced. Two valence electrons from each zinc atom are transferred to each sulfur atom.

What cage composed of 12 pairs of ribs, with their costal cartilages and the sternum, protects the heart and lungs?

cervical

sacral

lumbar

thoracic

7.4 The Thoracic Cage The thoracic cage protects the heart and lungs. It is composed of 12 pairs of ribs with their costal cartilages and the sternum. The ribs are anchored posteriorly to the 12 thoracic vertebrae. The sternum consists of the manubrium, body, and xiphoid process. The manubrium and body are joined at the sternal angle, which is also the site for attachment of the second ribs. Ribs are flattened, curved bones and are numbered 1–12. Posteriorly, the head of the rib articulates with the costal facets located on the bodies of thoracic vertebrae and the rib tubercle articulates with the facet located on the vertebral transverse process. The angle of the ribs forms the most posterior portion of the thoracic cage. The costal groove in the inferior margin of each rib carries blood vessels and a nerve. Anteriorly, each rib ends in a costal cartilage. True ribs (1–7) attach directly to the sternum via their costal cartilage. The false ribs (8–12) either attach to the sternum indirectly or not at all. Ribs 8–10 have their costal cartilages attached to the cartilage of the next higher rib. The floating ribs (11–12) are short and do not attach to the sternum or to another rib.

What is the ability of an atom to emit charged particles and energy from its nucleus called?

power

accumulation

conductivity

radioactivity

Radioactivity is the ability of an atom to emit charged particles and energy from its nucleus. The charged particles and energy are called by the general term radiation.

Diffusion is an effective transport mechanism over the spatial scales typically found at what level?

atom

electromagnetic

molecular

cellular

In a car race on a circular track, where the start and finish line are the same, what quantity is neglible?

total distance

total acceleration

partial displacement

total displacement

To return to the first image, these cars travel a distance of 500 miles over the course of the race. However, they are traveling in a circle, and the start and finish line are the same. Therefore, when the car finishes the race, it is in essentially the same position it was when it started. The car's total displacement is only a few feet.

What is another name for molecular compounds?

synthetic compounds

phenotype compounds

oxidized compounds

covalent compounds

The physical state and properties of a particular compound depend in large part on the type of chemical bonding it displays. Molecular compounds , sometimes called covalent compounds, display a wide range of physical properties due to the different types of intermolecular attractions such as different kinds of polar interactions. The melting and boiling points of molecular compounds are generally quite low compared to those of ionic compounds . This is because the energy required to disrupt the intermolecular forces between molecules is far less than the energy required to break the ionic bonds in a crystalline ionic compound. Since molecular compounds are composed of neutral molecules, their electrical conductivity is generally quite poor, whether in the solid or liquid state. Ionic compounds do not conduct electricity in the solid state because of their rigid structure, but conduct well when either molten or dissolved into a solution. The water solubility of molecular compounds is variable and depends primarily on the type of intermolecular forces involved. Substances that exhibit hydrogen bonding or dipole-dipole forces are generally water soluble, whereas those that exhibit only London dispersion forces are generally insoluble. Most, but not all, ionic compounds are quite soluble in water. Table below summarizes some of the differences between ionic and molecular compounds.

The long mouth-tube that some insects use to suck up the nectar of the flower is called what?

pistil

stamen

prosthesis

proboscis

Some insects use siphoning, as if sucking through a straw, like moths and butterflies. This long mouth-tube that they use to suck up the nectar of the flower is called a proboscis . Some moths, however, have no mouthparts at all. Some insects obtain food by sponging , like the housefly. Sponging means that the mouthpart can absorb liquid food and send it to the esophagus. The housefly is able to eat solid food by releasing saliva and dabbing it over the food. As the saliva dissolves the food, the sponging mouthpart absorbs the liquid food.

Cnvs result from regions of what being duplicated or deleted inconsistently within the population?

DNA

genes

cytoplasm

genome

Insects can have specialized mouthparts, such as a proboscis, to siphon the nectar from what?

fruits

stems

shrubs

flowers

Insects can have specialized mouthparts, such as a proboscis, to siphon the nectar from a flower.

What is the invisible force that pulls things to earth?

electromagnetism

motion

momentum

gravity

Gravity cannot be seen. It does not require things to touch. Gravity is an invisible force. Many things are pulled to the Earth by gravity. Can you think of some things that fall toward the Earth?.

What do we call the seasonal movement of animals?

immigration

population

trade

migration

Monarch butterflies gather in large groups as they migrate 2,500 miles south each fall. They return to the north in the spring. This migration is a cycle that repeats every year.

What kind of beneficial relationships with other organisms are common in the plant kingdom?

autotrophic

symbiotic

Host

mutualistic

Some marine algae have evolved special structures capable of what plant process?

seed germination

pollination

respiration

photosynthesis

in color. Golden algae are found in both freshwater and marine environments, where they form a major part of the plankton community. The brown algae are primarily marine, multicellular organisms that are known colloquially as seaweeds. Giant kelps are a type of brown algae. Some brown algae have evolved specialized tissues that resemble terrestrial plants, with root-like holdfasts, stem-like stipes, and leaf-like blades that are capable of photosynthesis. The stipes of giant kelps are enormous, extending in some cases for 60 meters. A variety of algal life cycles exists, but the most complex is alternation of generations, in which both haploid and diploid stages involve multicellularity. Compare this life cycle to that of humans, for instance. Haploid gametes produced by meiosis (sperm and egg) combine in fertilization to generate a diploid zygote that undergoes many rounds of mitosis to produce a multicellular embryo and then a fetus. However, the individual sperm and egg themselves never become multicellular beings. Terrestrial plants also have evolved alternation of generations. In the brown algae genus Laminaria, haploid spores develop into multicellular gametophytes, which produce haploid gametes that combine to produce diploid organisms that then become multicellular organisms with a different structure from the haploid form (Figure 23.19). Certain other organisms perform alternation of generations in which both the haploid and diploid forms look the same.

What is the substance called whenatoms of different elements join together?

plants

crusts

crystals

compounds

Did you ever make cupcakes from scratch? You mix together flour, sugar, eggs, and other ingredients to make the batter, put the batter into cupcake papers, and then put them into the oven to bake. The cupcakes that come out of the oven after baking are different from any of the individual ingredients that went into the batter. Like the ingredients that join together to make cupcakes, atoms of different elements can join together to form entirely different substances called compounds. In cupcakes, the eggs and other wet ingredients cause the dry ingredients to stick together. What causes elements to stick together in compounds? The answer is chemical bonds.

What type of solid has atoms arranged in a repeating pattern?

hydrocarbons

ions

metals

crystals

Some solids are not crystals. Glass, or the rock obsidian, are solid. However, they are not crystals. In a crystal , the atoms are arranged in a pattern. This pattern is regular and it repeats. The image below shows how the atoms are arranged in halite (table salt) ( Figure below ). Halite contains atoms of sodium and chlorine in a pattern. Notice that the pattern goes in all three dimensions.

What is the process called when secretory cells export products?

morphogenesis

endocytosis

isolation

exocytosis

Natural resources that are limited in supply and cannot be replaced except over millions of years are known as what?

renewable

precious

biological

nonrenewable

Nonrenewable resources are natural resources that are limited in supply and cannot be replaced except over millions of years. Nonrenewable energy resources include fossil fuels and radioactive elements such as uranium.

What is a hydrocarbon in which the carbon chain joins to itself in a ring?

acid hydrocarbon

asymmetrical hydrocarbon

circular hydrocarbon

cyclic hydrocarbon

A cyclic hydrocarbon is a hydrocarbon in which the carbon chain joins to itself in a ring. A cycloalkane is a cyclic hydrocarbon in which all of the carbon-carbon bonds are single bonds. Like other alkanes, cycloalkanes are saturated compounds. Cycloalkanes have the general formula of C n H 2n . The simplest cycloalkane is cyclopropane, a three-carbon ring.

The first photosynthetic organisms were not plants, but types of what that lived in the water?

algae

pathogens

fungi

bacteria

The first photosynthetic organisms were bacteria that lived in the water. So, where did plants come from? Evidence shows that plants evolved from freshwater green algae, a protist ( Figure below ). The similarities between green algae and plants is one piece of evidence. They both have cellulose in their cell walls, and they share many of the same chemicals that give them color. So what separates green algae from green plants?.

What is the second stage of photosynthesis?

glucose destruction

pigment release

production of protein

production of glucose

The second stage of photosynthesis is the production of glucose from carbon dioxide. This process occurs in a continuous cycle, named after its discover, Melvin Calvin. The Calvin cycle uses CO 2 and the energy temporarily stored in ATP and NADPH to make the sugar glucose.

Which layer is the lithosphere located?

nearest layer

eclipses layer

radii layer

outermost layer

Lithosphere and asthenosphere are layers based on physical properties. The outermost layer is the lithosphere . The lithosphere is the crust and the uppermost mantle. In terms of physical properties, this layer is rigid, solid, and brittle. It is easily cracked or broken.

What is speed at any given instant called?

relative speed

spontaneous speed

marginal speed

instantaneous speed

Speed may be constant, but often it varies from moment to moment. Speed at any given instant is called instantaneous speed. It is much more difficult to calculate than average speed.

During birth, a baby passes from the uterus through what organ to leave the body?

Esophagus

Ovary

the urethra

the vagina

The vagina is a cylinder-shaped organ that opens to the outside of the body. The other end joins with the uterus. Sperm deposited in the vagina swim up through the cervix, into the uterus, and from there into a fallopian tube. During birth, a baby passes from the uterus through the vagina to leave the body.

What type of earthquake creates a tsunami?

volcanic

Tectonic

collapse

underwater

An underwater earthquake creates a tsunami this way: the movement of the crust displaces water. The displacement forms a set of waves. The waves travel at jet speed through the ocean. Since the waves have low amplitudes and long wavelengths, they are unnoticed in deep water. As the waves reach shore they compress. They are also pushed upward by the shore. For these reasons, tsunamis can grow to enormous wave heights. Tsunami waves can cause tremendous destruction and loss of life. Fortunately, few undersea earthquakes generate tsunamis.

What is the smallest of the galilean moons?

aura

phoebe

demos

europa

Scientists think that Europa is a good place to look for extraterrestrial life. Europa is the smallest of the Galilean moons. The moon's surface is a smooth layer of ice. Scientists think that the ice may sit on top of an ocean of liquid water. How could Europa have liquid water when it is so far from the Sun? Europa is heated by Jupiter. Jupiter's tidal forces are so great that they stretch and squash its moon. This could produce enough heat for there to be liquid water. Numerous missions have been planned to explore Europa, including plans to drill through the ice and send a probe into the ocean. However, no such mission has yet been attempted.

What is the term for a combination of substances in which there is no chemical reaction?

a solution

a combination

a solute

a mixture

Like a chemical compound, a mixture consists of more than one chemical substance. Unlike a compound, a mixture does not have a fixed chemical composition. The substances in a mixture can be combined in any proportions. A mixture also does not involve a chemical reaction. Therefore, the substances in a mixture are not changed into unique new substances, and they can be separated from each other without a chemical reaction.

Where does the majority of chemical digestion occur?

large intestine

stomach

mouth

small intestine

Chemical digestion occurs when large food molecules are broken down into smaller nutrient molecules. This is a chemical process that begins in the mouth and stomach but occurs mainly in the small intestine.

The vertebrate endoskeleton includes a vertebral column, cranium, limbs, and what else?

blood girdles

tissue girdles

Skin Girdles

limb girdles

Vertebrate Endoskeletons. The vertebrate endoskeleton includes a vertebral column, cranium, limbs, and limb girdles. Can you find these parts in each endoskeleton shown here?.

What is defined as the velocity of the object at a given moment?

inertia

specific gravity

relativistic velocity

instantaneous velocity

The instantaneous velocity of an object is the velocity of the object at a given moment. If the object is moving with constant velocity, then the instantaneous velocity at every moment, the average velocity, and the constant velocity are all the same.

What is the term for an expression showing the relationship of the reaction rate to the concentrations of each reactant?

concentric law

decay law

flow law

rate law

The proportionality between the rate and becomes an equal sign by the insertion of a constant . A rate law is an expression showing the relationship of the reaction rate to the concentrations of each reactant. The specific rate constant is the proportionality constant relating the rate of the reaction to the concentrations of reactants. The rate law and the specific rate constant for any chemical reaction must be determined experimentally. The value of the rate constant is temperature dependent. A large value of the rate constant means that the reaction is relatively fast, while a small value of the rate constant means that the reaction is relatively slow.

How many pi bonds are found in a triple bond?

four

10

six

two

From the stirrup, the vibrations pass to the oval window . This is another membrane like the eardrum.

What is formed when an acidic solution and a basic solution react together in a neutralization reaction?

shallow

Sodium

seawater

salt

An acidic solution and a basic solution react together in a neutralization reaction that also forms a salt.

What is the causative agent of sleeping sickness in humans?

bacillus aerophilus

pseudomonas asplenii

escherichia coli

trypanosoma brucei

Figure 15.12 Trypanosoma brucei is the causative agent of sleeping sickness in humans. The mRNAs of this pathogen must be modified by the addition of nucleotides before protein synthesis can occur. (credit: modification of work by Torsten Ochsenreiter).

Living things that use energy to make food, both for themselves and other living things, are what part of an ecosystem?

growers

consumers

decomposers

producers

Producers are living things that use energy to make food. Producers make food for themselves and other living things. There are two types of producers:.

In science, what process produces evidence that helps answer questions and solve problems?

suspension

information

manipulation

investigation

Investigation is at the heart of science. It is how scientists do research. Scientific investigations produce evidence that helps answer questions and solve problems. If the evidence cannot provide answers or solutions, it may still be useful. It may lead to new questions or problems for investigation. As more knowledge is discovered, science advances.

What cellular structure is used during endocytosis to allow molecules to enter the cell?

membranes

nucleus

tissues

vesicles

What are unique about prokaryotic cells' organelles?

only membrane - bound

no cell walls

no epidermis

not membrane-bound

Diagram of a typical prokaryotic cell. Among other things, prokaryotic cells have a plasma membrane, cytoplasm, ribosomes, and DNA. Prokaryotes do not have membrane-bound organelles or a cell nucleus.

How long ago did the ancestors of mammals evolve?

100 million

10 million

50,900 million years

300 million years

Ancestors of mammals evolved close to 300 million years ago. They were amniotes called synapsids. Figure below shows how modern mammals evolved from synapsids. The stages of evolution from synapsids to mammals are described below.

A d. melanogaster population has an average heterozygosity of what?

22 %

19 %

21 %

14%

Traits that are affected by more than one gene are what type of traits?

dominant

monogenetic

recessive

polygenic traits

Traits that are affected by more than one gene are called polygenic traits . The genes that affect a polygenic trait may be closely linked on a chromosome, unlinked on a chromosome, or on different chromosomes. Polygenic traits are often difficult for geneticists to track because the polygenic trait may have many alleles. Also, independent assortment ensures the genes combine differently in gametes. Therefore, many different intermediate phenotypes exist in offspring. Eye color ( Figure below ), and skin color are examples of polygenic traits in humans.

Pharmacist and surveyor are two career options based in what type of science?

visible

obvious

Business

physical

There are many career options in physical science. Examples include pharmacist and surveyor.

What is another term for foodborne illness?

cancer

pathogen

disease

food poisoning

Harmful bacteria can enter your digestive system in food and make you sick. This is called foodborne illness or food poisoning. The bacteria, or the toxins they produce, may cause vomiting or cramping, in addition to the symptoms mentioned above. Foodborne illnesses can also be caused by viruses and parasites. The most common foodborne illnesses happen within a few minutes to a few hours, and make you feel really sick, but last for only about a day or so. Others can take longer for the illness to appear. Some people believe that the taste of food will tell you if it is bad. As a rule, you probably should not eat bad tasting food, but many contaminated foods can still taste good.

The mechanical advantage of a machine is related to how it changes what?

example

pressure

nature

force

The mechanical advantage of a machine is related to how it changes force. Explain this relationship.

What term in physics refers to the use of force to move an object?

velocity

mass

momentum

work

Work is defined differently in physics than in everyday language. In physics, work means the use of force to move an object. The teen who is playing tennis in Figure above is using force to move her tennis racket, so she is doing work. The teen who is studying isn’t moving anything, so she is not doing work.

What is the name of the organelle that helps make and transport proteins and lipids?

mitochondria

plasma membrane

nucleus

endoplasmic reticulum

The endoplasmic reticulum (ER) is an organelle that helps make and transport proteins and lipids. It’s made of folded membranes. Bits of membrane can pinch off to form tiny sacs called vesicles. The vesicles carry proteins or lipids away from the ER.

What machine is used to determine the calories in food, as well as the average heat yield from burning various grades of coal and oil?

alethiometer

radio telescope

thermometer

calorimeter

Though not particularly beautiful machines, calorimeters are incredibly useful ones. They are used to determine the calories (food energy) in food, as well as the average heat yield from burning various grades of coal and oil. The price of coal is often dependent on the heat yield from samples burned in a calorimeter.

What is the name of the outer part of the adrenal gland located above the kidneys?

spleen

nucleus

mitochondria

cortex

The two adrenal glands are located above the kidneys. Each gland has an inner and outer part. The outer part, called the cortex, secretes hormones such as cortisol, which helps the body deal with stress, and aldosterone, which helps regulate the balance of minerals in the body. The inner part of each adrenal gland, called the medulla, secretes fight-or-flight hormones such as adrenaline, which prepare the body to respond to emergencies. For example, adrenaline increases the amount of oxygen and glucose going to the muscles. You can see an animation of this response at the link below.

What kind of energy used heat from magma within the earth to heat homes or produce steam that turns turbines?

renewable energy

thermal energy

robust energy

geothermal energy

Geothermal energy uses heat from magma within the Earth to heat homes or produce steam that turns turbines.

The primary output of the basal nuclei is to the thalamus, which relays that output to where?

suffering cortex

effect cortex

Back cortex

cerebral cortex

Thalamus The thalamus is a collection of nuclei that relay information between the cerebral cortex and the periphery, spinal cord, or brain stem. All sensory information, except for the sense of smell, passes through the thalamus before processing by the cortex. Axons from the peripheral sensory organs, or intermediate nuclei, synapse in the thalamus, and thalamic neurons project directly to the cerebrum. It is a requisite synapse in any sensory pathway, except for olfaction. The thalamus does not just pass the information on, it also processes that information. For example, the portion of the thalamus that receives visual information will influence what visual stimuli are important, or what receives attention. The cerebrum also sends information down to the thalamus, which usually communicates motor commands. This involves interactions with the cerebellum and other nuclei in the brain stem. The cerebrum interacts with the basal nuclei, which involves connections with the thalamus. The primary output of the basal nuclei is to the thalamus, which relays that output to the cerebral cortex. The cortex also sends information to the thalamus that will then influence the effects of the basal nuclei.

The central nervous system is composed of the brain and what else?

the lateral cord

the sclerotic cord

the dynamic cord

the spinal cord

User:Grm_wnr/Wikimedia Commons, modified by CK-12 Foundation. The central nervous system is composed of the brain and the spinal cord . Public Domain.

A group of genetically identical individuals is called what?

a man

brother

replicant

a clone

Where on the earth's surface does the water cycle takes place?

inside,under,above

on , below , and below

for , above , and below

on, above, and below

The water cycle takes place on, above, and below Earth’s surface. In the cycle, water occurs as water vapor, liquid water, and ice. Many processes are involved as water changes state in the cycle. The atmosphere is an exchange pool for water. Ice masses, aquifers, and the deep ocean are water reservoirs.

Under which conditions do many bacteria carry out alcohol fermentation?

photosynthesis

melting

enzymatic

anaerobic

Fermat's principle states that what will always take the path that takes the least amount of time?

electricity

sound

wind

light

Light is a wave of changing electric and magnetic fields. Light waves are caused by disturbances in an electromagnetic field, like the acceleration of charged particles (such as electrons). Light has a dual nature; at times, it acts like waves, while at other times it acts like particles, called photons . Light travels through space at the maximum speed allowed by the laws of physics, called the speed of light. Light has no mass, but it carries energy and momentum. Fermat's principle states that light will always take the path that takes the least amount of time (not distance).

What trend is occurring involving the extent of arctic sea ice in summer?

Ice growth

slow decrease

water decrease

rapid decrease

The extent of Arctic sea ice in summer has been decreasing rapidly. The ice pictured below is the sea ice minimum in 2011 ( Figure below ). The yellow line is the median minimum ice extent for 1979–2000.

In vertebrates, cholesterol is synthesized in which organ and obtained from the diet?

heart

the bone

the brain

the liver

What is a group of lions called?

bevy

coven

herd

pride

Lions live in social groups called prides . Adult females in the pride hunt cooperatively, which is more efficient than hunting alone. Then they share the food with the rest of the pride. For their part, adult males defend the pride’s territory from other predators.

Which layer is found below the lithosphere?

stratosphere

troposphere

magnetosphere

asthenosphere

The asthenosphere is below the lithosphere. The asthenosphere is also in the upper mantle. This layer is solid, but it can flow and bend. A solid that can flow is like silly putty.

What is the name for the nonliving parts of ecosystems?

Dead factors

diverse factors

nucleic factors

abiotic factors

Abiotic factors are the nonliving parts of ecosystems. They include air, sunlight, soil, water, and minerals. These are all things that are needed for life. They determine which living things — and how many of them — an ecosystem can support. Figure below shows an ecosystem and its abiotic factors.

What do you call the electrons in the outermost energy level of an atom?

Proper electrons

Inner electrons

shell electrons

valence electrons

Electrons in the outermost energy level of an atom are called valence electrons. They determine many of the properties of an atom, including how reactive it is.

What are some of the giant fairy rings produced by?

sporangia

fronds

algae

mycelia

What are ingrowths on arthropod exoskeletons to which muscles attach?

rods

joints

pores

apodemes

Figure 33.3 Apodemes are ingrowths on arthropod exoskeletons to which muscles attach. The apodemes on this crab leg are located above and below the fulcrum of the claw. Contraction of muscles attached to the apodemes pulls the claw closed.

Which type of electrons plays the most important role in chemical reactions?

transition

noncovalent

intermediate

valence

Electron Configurations and the Periodic Table As described earlier, the periodic table arranges atoms based on increasing atomic number so that elements with the same chemical properties recur periodically. When their electron configurations are added to the table (Figure 6.30), we also see a periodic recurrence of similar electron configurations in the outer shells of these elements. Because they are in the outer shells of an atom, valence electrons play the most important role in chemical reactions. The outer electrons have the highest energy of the electrons in an atom and are most easily lost or shared than the core electrons. Valence electrons are also the determining factor in some physical properties of the elements. Elements in any one group (or column) have the same number of valence electrons; the alkali metals lithium and sodium each have only one valence electron, the alkaline earth metals beryllium and magnesium each have two, and the halogens fluorine and chlorine each have seven valence electrons. The similarity in chemical properties among.

What level is greater than 7 in a basic solution?

uh

fh

gh

ph

The solution is basic and so its pH is greater than 7. The reported pH is rounded to two decimal places because the original mass and volume has two significant figures.

What happens to volume as the temperature increases?

volume is unchanged

volume fluctuates

volume decreases

volume increases

The volume increases as the temperature increases. The result has three significant figures.

What does an array of radio telescopes collect?

microwaves

thermal waves

light waves

radio waves

Radio telescopes collect radio waves and are sometimes used in large arrays.

What kind of compounds contain positively and negatively charged ions in a ratio that results in an overall charge of zero?

zeronic ions

neutral compounds

zero charged compunds

ionic compounds

Summary The atoms in chemical compounds are held together by attractive electrostatic interactions known as chemical bonds. Ionic compounds contain positively and negatively charged ions in a ratio that results in an overall charge of zero. The ions are held together in a regular spatial arrangement by electrostatic forces. Mostcovalent compounds consist of molecules, groups of atoms in which one or more pairs of electrons are shared by at least two atoms to form a covalent bond. The atoms in molecules are held together by the electrostatic attractionbetween the positively charged nuclei of the bonded atoms and the negatively charged electrons shared by the nuclei. The molecular formula of a covalent compound gives the types and numbers of atoms present. Compounds that contain predominantly carbon and hydrogen are called organic compounds, whereas compounds that consist primarily of elements other than carbon and hydrogen areinorganic compounds. Diatomic molecules contain two atoms, andpolyatomic molecules contain more than two. A structural formula indicates the composition and approximate structure and shape of a molecule. Single bonds, double bonds, and triple bonds are covalent bonds in which one, two, and three pairs of electrons, respectively, are shared between two Saylor URL: http://www. saylor. org/books.

What are formed when crystals precipitate out from a liquid?

gaseous sedimentary rocks

diamonds

additive sedimentary rocks

chemical sedimentary rocks

Chemical sedimentary rocks form when crystals precipitate out from a liquid. The mineral halite, also called rock salt, forms this way. You can make halite! Leave a shallow dish of salt water out in the Sun. As the water evaporates, salt crystals form in the dish. There are other chemical sedimentary rocks, like gypsum ( Figure below ).

Roundworms exemplify what type of organization, where two or more types of tissues work together to perform a particular function as an organ?

delicate - level organization

bone-level organization

land-level organization

organ-level organization

Roundworms have organ-level organization, in which two or more types of tissues work together to perform a particular function as an organ. For example, a roundworm has a primitive brain that controls how the organism responds to the environment.

Where are protons and neutrons located?

epidermis

radius

electron shell

nucleus

Unlike protons and neutrons, which are located inside the nucleus at the center of the atom, electrons are found outside the nucleus. Because opposite electric charges attract each other, negative electrons are attracted to the positive nucleus. This force of attraction keeps electrons constantly moving through the otherwise empty space around the nucleus. The Figure below is a common way to represent the structure of an atom. It shows the electron as a particle orbiting the nucleus, similar to the way that planets orbit the sun.

Why do hummingbirds have long narrow bills?

for protection against predators

to feed their offspring

to store food

to reach the nectar at the bottom of flowers

dome-shaped plug of thick lava that cools near the vent of a volcano.

Bivalvia and gastropoda are classes of what phylum?

diatoms

Insects

fishes

mollusks

Which of the following statements about the anatomy of a mollusk is false? a. Mollusks have a radula for scraping food. Mollusks have ventral nerve cords. The tissue beneath the shell is called the mantle. The mantle cavity contains hemolymph. Mollusk Diversity This phylum is comprised of seven classes: Aplacophora, Monoplacophora, Polyplacophora, Bivalvia, Gastropoda, Cephalopoda, and Scaphopoda. Class Aplacophora (“bearing no plates”) includes worm-like animals living mostly on deep ocean bottoms. These animals lack a shell but have aragonite spicules on their skin. Members of class Monoplacophora (“bearing one plate”) have a single, cap-like shell enclosing the body. The monoplacophorans were believed extinct and only known as fossils until the discovery of Neopilina galatheae in 1952. Today, scientists have identified nearly two dozen living species. Animals in the class Polyplacophora (“bearing many plates”) are commonly known as “chitons” and bear an armor-like, eight-plated shell (Figure 15.25). These animals have a broad, ventral foot that is adapted for attachment to rocks and a mantle that extends beyond the shell in the form of a girdle. They breathe with ctenidia (gills) present ventrally. These animals have a radula modified for scraping. A single pair of nephridia for excretion is present.

Kinetic energy of moving particles of matter, measured by their temperatures are known as:

solar energy

visible energy

atmospheric energy

thermal energy

Heat is the transfer of thermal energy between substances. Thermal energy is the kinetic energy of moving particles of matter, measured by their temperature. Thermal energy always moves from matter with greater thermal energy to matter with less thermal energy, so it moves from warmer to cooler substances. You can see this in the Figure below . Faster-moving particles of the warmer substance bump into and transfer some of their energy to slower-moving particles of the cooler substance. Thermal energy is transferred in this way until both substances have the same thermal energy and temperature. For a visual introduction to these concepts, watch the animation “Temperature vs. Heat” at this URL:.

What is the term for a process that changes some chemical substances into others?

chain reaction

acid reaction

toxic reaction

chemical reaction

A chemical reaction is a process that changes some chemical substances into others. During a chemical reaction, the reactants are used up to create the products.