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What allows giraffes to reach leaves that other ground animals cannot? | long horns | camouflage pattern | long tongue | long necks | African Giraffes. Giraffes feed on leaves high in trees. Their long necks allow them to reach leaves that other ground animals cannot. |
Chemical formulas for ionic compounds are called what? | magnetic formulas | electronic formulas | velocity formulas | ionic formulas | Chemical formulas for ionic compounds are called ionic formulas. A proper ionic formula has a cation and an anion in it; an ionic compound is never formed between two cations only or two anions only. The key to writing proper ionic formulas is simple: the total positive charge must balance the total negative charge. Because the charges on the ions are characteristic, sometimes we have to have more than one of a cation or an anion to balance the overall positive and negative charges. It is conventional to use the lowest ratio of ions that are needed to balance the charges. For example, consider the ionic compound between Na+ and Cl−. Each ion has a single charge, one positive and one negative, so we need only one ion of each to balance the overall charge. When writing the ionic formula, we follow two additional conventions: (1) write the formula for the cation first and the formula for the anion next, but (2) do not write the charges on the ions. Thus, for the compound between Na+ and Cl−, we have the ionic formula NaCl (Figure 3.5 "NaCl = Table Salt"). The formula Na2Cl2 also has balanced charges, but the convention is to use the lowest ratio of ions, which would be one of each. (Remember from our conventions for writing formulas that we don’t write a 1 subscript if there is only one atom of a particular element present. ) For the ionic compound between magnesium cations (Mg2+) and oxide anions (O2−), again we need only one of each ion to balance the charges. By convention, the formula is MgO. For the ionic compound between Mg2+ ions and Cl− ions, we now consider the fact that the charges have different magnitudes, 2+ on the magnesium ion and 1− on the chloride ion. To balance the charges with the lowest number of ions possible, we need to have two chloride ions Saylor URL: http://www. saylor. org/books. |
What term is used to describe the full range of electromagnetic waves? | mechanical spectrum | electromagnetic scale | electromagnetic series | electromagnetic spectrum | Electromagnetic waves vary in their wavelength, frequency, and energy. The full range of electromagnetic waves makes up the electromagnetic spectrum. |
How many lobes is each hemisphere of the cerebrum divided into? | 5 | 9 | 2 | 4 | Each hemisphere of the cerebrum is divided into four parts, called lobes. The four lobes are the:. |
Varicose veins are veins that become enlarged because the valves no longer do this? | enlarge properly | shrink properly | open properly | close properly | Blood travels through the bicuspid valve to the left atrium. Both the aortic and the pulmonary valves are semilunar valves. The mitral valve is an atrioventricular valve. Figure 40.17 Varicose veins are veins that become enlarged because the valves no longer close properly, allowing blood to flow backward. Varicose veins are often most prominent on the legs. Why do you think this is the case?. |
Liquids with strong intermolecular forces have higher what than liquids with weaker forces? | freezing point | temperature | melting point | surface tension | Liquids with strong intermolecular forces have higher surface tensions than liquids with weaker forces. |
What kind of volcanoes often form along divergent plate boundaries? | crest | composite | dome | shield | Shield volcanoes often form along divergent plate boundaries. They also form at hotspots, like Hawaii. Shield volcano eruptions are non-explosive. |
An element symbol without a charge written next to it is assumed to be what? | surfactants atom | dead atom | corroborate atom | uncharged atom | Third, there are some exceptions to the previous point. A few elements, all metals, can form more than one possible charge. For example, iron atoms can form 2+ cations or 3+ cations. Cobalt is another element that can form more than one possible charged ion (2+ and 3+), while lead can form 2+ or 4+ cations. Unfortunately, there is little understanding which two charges a metal atom may take, so it is best to just memorize the possible charges a particular element can have. Note the convention for indicating an ion. The magnitude of the charge is listed as a right superscript next to the symbol of the element. If the charge is a single positive or negative one, the number 1 is not written; if the magnitude of the charge is greater than 1, then the number is written before the + or − sign. An element symbol without a charge written next to it is assumed to be the uncharged atom. Naming an ion is straightforward. For a cation, simply use the name of the element and add the word ion (or if you want to be more specific, add cation) after the element’s name. So Na+ is the sodium ion; Ca2+ is the calcium ion. If the element has more than one possible charge, the value Saylor URL: http://www. saylor. org/books. |
What is the fundamental unit of structure and function in all living organisms? | the vessels | the spinal cord | the backbone | the cell | the cell is the fundamental unit of structure and function in all living organisms,. |
What characteristic of particles determines how they are carried by flowing water? | texture | density | color | size | The size of particles determines how they are carried by flowing water. This is illustrated in Figure below . |
What term refers to something supplied by nature that helps support life? | existing resource | free resource | simple resource | natural resource | A natural resource is something supplied by nature that helps support life. When you think of natural resources, you may think of fossil fuels, like the coal in the coal field pictured in Figure below . However, sunlight, wind, soil, and living things are also important natural resources. |
What is the shape of the orbits that planets make around the sun? | elongated | conical | variable | elliptical | The planets make slightly elliptical orbits around the Sun. |
What are chlamydia, gonorrhea, and syphilis an example of? | viral stis | metabolic disorders | genetic diseases | bacterial stis | A sexually transmitted infection (STI) is a disease that spreads mainly through sexual contact. STIs are more common in teens and young adults than in older people. Bacterial STIs include chlamydia, gonorrhea, and syphilis. Viral STIs include genital warts, genital herpes, and AIDS. |
What organism are resistant to freezing and drying and also are metabolically inactive? | trichina | giardia | spirogyra | zygosporangia | |
What is produced during a condensation reaction? | fire | rain | wind | water | Condensation reactions are the chemical processes by which large organic compounds are synthesized from their monomeric units. Hydrolysis reactions are the reverse process. During condensation reactions, water is produced from the two molecules being bonded together; an H from one monomer is joined to an -OH from another molecule, producing H 2 O. |
What force pulls objects toward the center of the earth? | momentum | kinetic energy | centrifugal force | gravity | |
Where are protons and neutrons located? | orbitals | outside the nucleus | secondary nucleus | central nucleus | Protons and neutrons are located in a central nucleus, while electrons orbit about the nucleus. |
What is a measurement of the amount of variation of the species in a given area called? | degradation | ecosystem | population | biodiversity | Biodiversity is a measurement of the amount of variation of the species in a given area. More specifically, biodiversity can be defined as the variety of life and its processes, including the variety of living organisms, the genetic differences among them, and the communities and ecosystems in which they occur. |
Deleting or inserting a nitrogen base causes what? | a photoinhibition mutation | a placentation mutation | a degenerative mutation | a frameshift mutation | Deleting or inserting a nitrogen base causes a frameshift mutation. All of the codons following the mutation are misread. This may be disastrous. To see why, consider this English-language analogy. Take the sentence “The big dog ate the red cat. ” If the second letter of “big” is deleted, then the sentence becomes: “The bgd oga tet her edc at. ” Deleting a single letter makes the rest of the sentence impossible to read. |
What are the chemical messengers used to communicate between cells? | neurons | membranes | peptides | hormones | Hormones, chemical messengers used to communicate between cells, are important in regulating digestion. |
Graphite and diamond both are made from carbon. what makes diamonds so hard? | strong light network | weak atomic network | strong metallic network | strong atomic network | Sometimes two different minerals have the same chemical composition. But they are different minerals because they have different crystal structures. Diamonds are beautiful gemstones because they are very pretty and very hard. Graphite is the “lead” in pencils. It's not hard at all! Amazingly, both are made just of carbon. Compare the diamond with the pencil lead in Figure below . Why are they so different? The carbon atoms in graphite bond to form layers. The bonds between each layer are weak. The carbon sheets can just slip past each other. The carbon atoms in diamonds bond together in all three directions. This strong network makes diamonds very hard. |
The paranasal sinuses are hollow, air-filled spaces located within certain bones of the skull. all of the sinuses communicate with the nasal cavity (paranasal = “next to nasal cavity”) and are lined with this? | fluid mucosa | respiration mucosa | oral mucosa | nasal mucosa | Paranasal Sinuses The paranasal sinuses are hollow, air-filled spaces located within certain bones of the skull (Figure 7.18). All of the sinuses communicate with the nasal cavity (paranasal = “next to nasal cavity”) and are lined with nasal mucosa. They serve to reduce bone mass and thus lighten the skull, and they also add resonance to the voice. This second feature is most obvious when you have a cold or sinus congestion. These produce swelling of the mucosa and excess mucus production, which can obstruct the narrow passageways between the sinuses and the nasal cavity, causing your voice to sound different to yourself and others. This blockage can also allow the sinuses to fill with fluid, with the resulting pressure producing pain and discomfort. The paranasal sinuses are named for the skull bone that each occupies. The frontal sinus is located just above the eyebrows, within the frontal bone (see Figure 7.17). This irregular space may be divided at the midline into bilateral spaces, or these may be fused into a single sinus space. The frontal sinus is the most anterior of the paranasal sinuses. The largest sinus is the maxillary sinus. These are paired and located within the right and left maxillary bones, where they occupy the area just below the orbits. The maxillary sinuses are most commonly involved during sinus infections. Because their connection to the nasal cavity is located high on their medial wall, they are difficult to drain. The sphenoid sinus is a single, midline sinus. It is located within the body of the sphenoid bone, just anterior and inferior to the sella turcica, thus making it the most posterior of the paranasal sinuses. The lateral aspects of the ethmoid bone contain multiple small spaces separated by very thin bony walls. Each of these spaces is called an ethmoid air cell. These are located on both sides of the ethmoid bone, between the upper nasal cavity and medial orbit, just behind the superior nasal conchae. |
What determines the strength of a base when dissolved in water? | saline content | amount of phosphorus ions produced | pH level | amount of hydroxide ions produced | The strength of a base depends on how many hydroxide ions it produces when it dissolves in water. A stronger base produces more hydroxide ions than a weaker base. For example, sodium hydroxide (NaOH), a base in drain cleaner, is a strong base because all of it breaks down into ions when it dissolves in water. Calcium carbonate (CaCO 3 ), a base in antacids, is a weak base because only a small percentage of it breaks down into ions in water. |
What is the low level of radiation that occurs naturally in the environment called? | consequence radiation | temperature radiation | neon radiation | background radiation | A low level of radiation occurs naturally in the environment. This is called background radiation. It comes from various sources. One source is rocks, which may contain small amounts of radioactive elements such as uranium. Another source is cosmic rays. These are charged particles that arrive on Earth from outer space. Background radiation is generally considered to be safe for living things. |
Varicella zoster virus causes what two illnesses? | syphilis and lyme | flu and shingles | german measles and flu | chicken pox and shingles | An enveloped virus. Varicella zoster virus causes chicken pox and shingles. |
The urethra transports urine from what organ to the outside of the body for disposal? | brain | heart | lungs | bladder | Urethra The urethra transports urine from the bladder to the outside of the body for disposal. The urethra is the only urologic organ that shows any significant anatomic difference between males and females; all other urine transport structures are identical (Figure 25.3). |
Magnetite crystals in lava typically point to what geographic location? | geographic north pole | the equator | magnetic south pole | magnetic north pole | Magnetite crystals in the lava point in the direction of the magnetic north pole. The different stripes of magnetic polarity reveal the different ages of the seafloor. |
Liquids that mix with water in all proportions are usually polar substances or substances that form these? | compressed bonds | silicon bonds | atmospheric bonds | hydrogen bonds | Liquids that mix with water in all proportions are usually polar substances or substances that form hydrogen bonds. For such liquids, the dipole-dipole attractions (or hydrogen bonding) of the solute molecules with the solvent molecules are at least as strong as those between molecules in the pure solute or in the pure solvent. Hence, the two kinds of molecules mix easily. Likewise, nonpolar liquids are miscible with each other because there is no appreciable difference in the strengths of solute-solute, solvent-solvent, and solute-solvent intermolecular attractions. The solubility of polar molecules in polar solvents and of nonpolar molecules in nonpolar solvents is, again, an illustration of the chemical axiom “like dissolves like. ” Two liquids that do not mix to an appreciable extent are called immiscible. Layers are formed when we pour immiscible liquids into the same container. Gasoline, oil (Figure 11.15), benzene, carbon tetrachloride, some paints, and many other nonpolar liquids are immiscible with water. The attraction between the molecules of such nonpolar liquids and polar water molecules is ineffectively weak. The only strong attractions in such a mixture are between the water molecules, so they effectively squeeze out the molecules of the nonpolar liquid. The distinction between immiscibility and miscibility is really one of degrees, so that miscible liquids are of infinite mutual solubility, while liquids said to be immiscible are of very low (though not zero) mutual solubility. |
Lattice energy cannot be measured directly. what is its calculation based on? | microscopic inspection | chemical reactions | change in temperature | measured energy changes | There are a number of different ways to measure the strength of a given crystal lattice. One way would be to measure the amount of energy needed to completely pull apart an ionic substance into isolated ions. This value, known as the lattice energy , cannot be measured directly, but it can be calculated based on measured energy changes for other more feasible processes. The lattice energy of an ionic solid provides us with one way to measure the relative strength of the ionic bonds in that compound. Table below shows the lattice energies for various ionic substances:. |
What process provides over 99% of the energy supply for life on earth? | Carbon | gases | nutrients | photosynthesis | Photosynthesis provides over 99% of the energy supply for life on Earth. A much smaller group of autotrophs - mostly bacteria in dark or low-oxygen environments - produce food using the chemical energy stored in inorganic molecules such as hydrogen sulfide, ammonia, or methane. While photosynthesis transforms light energy to chemical energy, this alternate method of making food transfers chemical energy from inorganic to organic molecules. It is therefore called chemosynthesis , and is characteristic of the tubeworms shown in Figure below . Some of the most recently discovered chemosynthetic bacteria inhabit deep ocean hot water vents or “black smokers. ” There, they use the energy in gases from the Earth’s interior to produce food for a variety of unique heterotrophs: giant tube worms, blind shrimp, giant white crabs, and armored snails. Some scientists think that chemosynthesis may support life below the surface of Mars, Jupiter's moon, Europa, and other planets as well. Ecosystems based on chemosynthesis may seem rare and exotic, but they too illustrate the absolute dependence of heterotrophs on autotrophs for food. |
What type of animal are most reptiles in regards to diet? | arthropods | herbivores | omnivores | carnivores | Most reptiles are carnivores, and large reptiles are the top predators in their ecosystems. |
Because of their reactivity, we do not find most representative metals as free elements where? | underground | in water | in the atomospher | in nature | [PCl 3][Cl 2] (0.135)(0.135) = = 0.021 0.87 [PCl 5] The equilibrium constant calculated from the equilibrium concentrations is equal to the value of Kc given in the problem (when rounded to the proper number of significant figures). Thus, the calculated equilibrium concentrations check. Kc =. |
Two important concepts, niche and habitat, are associated with what? | water | natural selection | plant | ecosystem | Two important concepts associated with the ecosystem are niche and habitat. |
When does diseases like alzheimer's become more common? | i-40 age | toddler | teenager | old age | Old age begins in the mid-60s and lasts until the end of life. Most people over 65 have retired from work, freeing up their time for hobbies, grandchildren, and other interests. Stamina, strength, reflex time, and the senses all decline during old age, and the number of brain cells decreases as well. The immune system becomes less efficient, increasing the risk of serious illnesses such as cancer and pneumonia. Diseases such as Alzheimer’s disease that cause loss of mental function also become more common. |
What is a fibrocartilaginous pad that fills the gap between adjacent vertebral bodies? | subsidence disc | unidirectional disc | Back Disk | intervertebral disc | Intervertebral Disc An intervertebral disc is a fibrocartilaginous pad that fills the gap between adjacent vertebral bodies (see Figure 7.24). Each disc is anchored to the bodies of its adjacent vertebrae, thus strongly uniting these. The discs also provide padding between vertebrae during weight bearing. Because of this, intervertebral discs are thin in the cervical region and thickest in the lumbar region, which carries the most body weight. In total, the intervertebral discs account for approximately 25 percent of your body height between the top of the pelvis and the base of the skull. Intervertebral discs are also flexible and can change shape to allow for movements of the vertebral column. Each intervertebral disc consists of two parts. The anulus fibrosus is the tough, fibrous outer layer of the disc. It forms a circle (anulus = “ring” or “circle”) and is firmly anchored to the outer margins of the adjacent vertebral bodies. Inside is the nucleus pulposus, consisting of a softer, more gel-like material. It has a high water content that serves to resist compression and thus is important for weight bearing. With increasing age, the water content of the nucleus pulposus gradually declines. This causes the disc to become thinner, decreasing total body height somewhat, and reduces the flexibility and range of motion of the disc, making bending more difficult. The gel-like nature of the nucleus pulposus also allows the intervertebral disc to change shape as one vertebra rocks side to side or forward and back in relation to its neighbors during movements of the vertebral column. Thus, bending forward causes compression of the anterior portion of the disc but expansion of the posterior disc. If the posterior anulus fibrosus is weakened due to injury or increasing age, the pressure exerted on the disc when bending forward and lifting a heavy object can cause the nucleus pulposus to protrude posteriorly through the anulus fibrosus, resulting in a herniated disc (“ruptured” or “slipped” disc) (Figure 7.30). The posterior bulging of the nucleus pulposus can cause compression of a spinal nerve at the point where it exits through the intervertebral foramen, with resulting pain and/or muscle weakness in those body regions supplied by that nerve. The most common sites for disc herniation are the L4/L5 or L5/S1 intervertebral discs, which can cause sciatica, a widespread pain that radiates from the lower back down the thigh and into the leg. Similar injuries of the C5/C6 or C6/C7 intervertebral discs, following forcible hyperflexion of the neck from a collision accident or football injury, can produce pain in the neck, shoulder, and upper limb. |
What organic catalysts work by lowering the activation energy needed to start biochemical reactions? | glucose | hormones | carbohydrates | enzymes | Enzymes work by lowering the activation energy needed to start biochemical reactions. |
What structure supports the body, protects internal organs, produces blood cells, and maintains mineral homeostasis? | cuticle | fossil | skin | skeleton | The skeleton supports the body, protects internal organs, produces blood cells, and maintains mineral homeostasis. |
When vertebrate animals metabolize ammonia what is the primary byproduct that is produced? | proteins | carbon monoxide | dioxide | urea | 41.4 Nitrogenous Wastes Ammonia is the waste produced by metabolism of nitrogen-containing compounds like proteins and nucleic acids. While aquatic animals can easily excrete ammonia into their watery surroundings, terrestrial animals have evolved special mechanisms to eliminate the toxic ammonia from their systems. Urea is the major byproduct of ammonia metabolism in vertebrate animals. Uric acid is the major byproduct of ammonia metabolism in birds, terrestrial arthropods, and reptiles. |
Which process involves solvent separation on a solid medium? | affinity | substration | resonance | chromatography | Chromatography involves solvent separation on a solid medium. |
Plasmodesmata and gap junctions are channels between adjacent cells of what respective types? | plant and fungus | healthy and sick | new and old | plant and animal | 4.6 Connections between Cells and Cellular Activities Animal cells communicate via their extracellular matrices and are connected to each other via tight junctions, desmosomes, and gap junctions. Plant cells are connected and communicate with each other via plasmodesmata. When protein receptors on the surface of the plasma membrane of an animal cell bind to a substance in the extracellular matrix, a chain of reactions begins that changes activities taking place within the cell. Plasmodesmata are channels between adjacent plant cells, while gap junctions are channels between adjacent animal cells. However, their structures are quite different. A tight junction is a watertight seal between two adjacent cells, while a desmosome acts like a spot weld. |
Natural gas burns cleaner and produces less carbon dioxide than fuels of what type? | biofuels | renewable fuels | solar energy | fossil fuels | Natural gas burns cleaner than other fossil fuels. As a result, it causes less air pollution. It also produces less carbon dioxide than the other fossil fuels. Because it burns cleaner than other fossil fuels, natural gas has a good reputation. Still, natural gas does emit pollutants. |
What are the simplest types of carbon-based compounds? | Cells | particles | Microbes | hydrocarbons | Hydrocarbons are compounds that contain only carbon and hydrogen. They are the simplest type of carbon-based compounds. |
What process moves food through the esophagus no matter which position the body is in? | homeostasis | mastication | proteolysis | peristalsis | Some people think that gravity moves food through the esophagus. If that were true, food would move through the esophagus only when you are sitting or standing upright. In fact, because of peristalsis, food can move through the esophagus no matter what position you are in—even upside down! Just don’t try to swallow food when you are upside down—you could choke!. |
The female reproductive organs include the ovaries, fallopian tubes, uterus, and what? | bladder | intestines | womb | vagina | The female reproductive organs include the ovaries, fallopian tubes, uterus, and vagina. |
What do offsprings obtain from their parents in what is called, inheritance? | attributes | variations | mutations | characteristics | |
Warming up your body before a workout does what to the blood flow? | minimizes it | reduces it | stops it | increases it | Sometimes muscles and tendons get injured when a person starts doing an activity before they have warmed up properly. A warm up is a slow increase in the intensity of a physical activity that prepares muscles for an activity. Warming up increases the blood flow to the muscles and increases the heart rate. Warmed-up muscles and tendons are less likely to get injured. For example, before running or playing soccer, a person might jog slowly to warm muscles and increase their heart rate. Even elite athletes need to warm up ( Figure below ). |
What is a substance that increases the hydrogen ion concentration of a solution? | base | carbon | sulfur | acid | |
Scientists ask questions, and then make detailed observations to try to ask more specific questions, in order to develop what? | theories | Tests | suggests | hypothesis | A scientist is always trying to find the truth and discover new truths. How can you think like a scientist? Thinking like a scientist is based on asking and answering questions. Though you may not know it, you do this all day long. Scientists ask questions, and then make detailed observations to try to ask more specific questions and develop a hypothesis . They may design and perform an experiment to try to answer their question and test their hypothesis. From the results of their experiment, scientists draw conclusions . A conclusion describes what the evidence tells the scientist. |
What is the main difference between prokaryotic or eukaryotic cells ? | the presence of a Golgi Apparatus | the type of metabolic waste | the presence of cell walls | the presence of a nucleus | The answer depends on if the cell is prokaryotic or eukaryotic. The main difference between the two types of cells is the presence of a nucleus. And in eukaryotic cells, DNA lives in the nucleus. |
Supercontinents have formed at least how many times in earth history? | two | twenty | nine | five | The first continents were small but they grew over time. Supercontinents have formed at least five times in Earth history. |
How are layers of the atmosphere divided? | density gradients | air gradients | color gradients | temperature gradients | The layers of the atmosphere are divided by their temperature gradients. The lowest layer is the troposphere. All weather takes place in this layer. The next layer is the stratosphere. The stratosphere contains the protective ozone layer. More sunlight strikes at the Equator than at the poles. This is what drives the global winds. Warm air rises, moves poleward, and then sinks when it meets with air moving toward the Equator. The result is six atmospheric circulation cells around the world. There are three cells in each hemisphere. Pollutants enter the atmosphere from a few sources. The most important is fossil fuel burning. Air pollution has bad effects on the environment and on human health. By reducing fossil fuel use we can make the environment cleaner. When ozone depletion was found to be a problem, the world acted. As a result, the ozone hole has stabilized. The hole will be getting smaller over the next decades. |
What term is used to describe molecules that contain carbon-nitrogen bonds? | nitrites | compounds | ions | amines | Amines are molecules that contain carbon-nitrogen bonds. The nitrogen atom in an amine has a lone pair of electrons and three bonds to other atoms, either carbon or hydrogen. Various nomenclatures are used to derive names for amines, but all involve the class-identifying suffix –ine as illustrated here for a few simple examples:. |
Birds have a flow-through respiratory system in which air flows unidirectionally from the posterior sacs into the lungs, then into these? | alveoli | posterior bronchi | gills | anterior air sacs | Figure 39.14 (a) Birds have a flow-through respiratory system in which air flows unidirectionally from the posterior sacs into the lungs, then into the anterior air sacs. The air sacs connect to openings in hollow bones. (b) Dinosaurs, from which birds descended, have similar hollow bones and are believed to have had a similar respiratory system. (credit b: modification of work by Zina Deretsky, National Science Foundation). |
What are convection currents that occur far below the surface of the ocean called? | flat currents | subsequent currents | waves | deep currents | Deep currents are convection currents that occur far below the surface. They are caused by differences in the density of ocean water. |
Cations are attracted to anions, which are ions with what charge? | positive | similar | neutral | negative | 2.2 Chemical Bonds Each moment of life, atoms of oxygen, carbon, hydrogen, and the other elements of the human body are making and breaking chemical bonds. Ions are charged atoms that form when an atom donates or accepts one or more negatively charged electrons. Cations (ions with a positive charge) are attracted to anions (ions with a negative charge). This attraction is called an ionic bond. In covalent bonds, the participating atoms do not lose or gain electrons, but rather share them. Molecules with nonpolar covalent bonds are electrically balanced, and have a linear three-dimensional shape. Molecules with polar covalent bonds have “poles”—regions of weakly positive and negative charge—and have a triangular three-dimensional shape. An atom of oxygen and two atoms of hydrogen form water molecules by means of polar covalent bonds. Hydrogen bonds link hydrogen atoms already participating in polar covalent bonds to anions or electronegative regions of other polar molecules. Hydrogen bonds link water molecules, resulting in the properties of water that are important to living things. |
A non-bony skeleton that forms outside of the body is known as a what? | endoskeleton | excitoskeleton | exoplate | exoskeleton | One way early land invertebrates solved these problems was with an exoskeleton. This is a non-bony skeleton that forms on the outside of the body. It supports the body and helps it retain water. As the organism grows, it sheds its old exoskeleton and grows a new one. Figure below shows the discarded exoskeleton of a dragonfly. |
The vagina connects to which internal organ? | ovaries | artery | valves | uterus | The vagina is a cylinder-shaped organ found inside of the female body. One end of the vagina opens at the outside of the body. The other end joins with the uterus. During sexual intercourse, sperm may be released into the vagina. If this occurs, the sperm will move through the vagina and into the uterus. During birth, a baby passes from the uterus to the vagina to leave the body. |
What is the measure of electric current? | volts | intensity | watts | ampheres | One advantage of anaerobic respiration is obvious. It lets organisms live in places where there is little or no oxygen. Such places include deep water, soil, and the digestive tracts of animals such as humans (see Figure below ). |
Name a passageway that is shared with the digestive system. | larynx | esophagus | trachea | pharynx | Next, air passes through the pharynx, a passageway that is shared with the digestive system. From the pharynx, the air passes next through the larynx, or voice box. |
What substances function as a long-term energy store in the human body and possess long carbon chains that prevent dissolving in water? | nanoparticles | hydrocarbons | steroids | triglycerides | Triglycerides function as a long-term storage form of energy in the human body. Because of the long carbon chains, triglycerides are nearly nonpolar molecules and thus do not dissolve readily in polar solvents such as water. Instead, oils and fats are soluble in nonpolar organic solvents such as hexane and ethers. |
Thermal, radiant, electrical, nuclear, and chemical are all types of what? | heating | fuel | fuel | energy | The chapter describes thermal energy, radiant energy, electrical energy, nuclear energy, and chemical energy. Which form(s) of energy are represented by each of the following?. |
Coronary arteries ans small in what? | length | density | height | diameter | |
What occurs when a substance reacts quickly with oxygen? | catalytic conversion | convection | oxidation | combustion reaction | A combustion reaction occurs when a substance reacts quickly with oxygen (O 2 ). You can see an example of a combustion reaction in Figure below . Combustion is commonly called burning. The substance that burns is usually referred to as fuel. The products of a combustion reaction include carbon dioxide (CO 2 ) and water (H 2 O). The reaction typically gives off heat and light as well. The general equation for a combustion reaction can be represented by:. |
What are the two basic types of competition called? | interference and interaction | exploitative and beneficial | weak and strong | instraspecifc and interspecific | Aggressive behavior often occurs when individuals compete for the same resources. Animals may compete for territory, water, food, or mates. There are two basic types of competition: intraspecific and interspecific. |
Algae are much simpler than protozoa. they are aquatic and contain this? | cloning factor | testes | sporozoa | chlorophyll | 22.11 Algae Algae are much simpler than protozoa. They are aquatic and contain chlorophyll. Algae can exist as a single cell or as giant seaweeds 60 m in length. Formerly, algae were classified as plants but this was incorrect as algae lack parts of true plants: leaves, stems, roots, xylem, and phloem. Since algae belong in the kingdom Protista, algae is a broad term used to denote all aquatic eukaryotes which photosynthesise; algae can differ in size and shape as well. There are six phyla of algae:chlorophytes (green algae), phaeophytes (brown algae), rhodophytes (red algae), chrysophytes (diatoms), pyrrophytes (dinoflagellates), and euglenophytes (euglenoids). |
What is a gram stain used to identify ? | different types of liquids | radioactivity | acids or bases | different types of bacteria | Different types of bacteria stain a different color when Gram stain is applied to them. This makes them easy to identify. Some stain purple and some stain red, as you can see in Figure below . The two types differ in their outer layers. This explains why they stain differently. |
Burning gas to run our cars is an example of how human activity is contributing to what global event? | metamorphic change | ozone change | carbon change | climate change | Flickr:futureatlas. com (http://futureatlas. com/blog/). Human activities like burning gasoline in cars are contributing to a global change in our climate . CC BY 2.0. |
The periodic table of elements is divided into what? | groups | patterns | spheres | squares | Each element has its own square in the periodic table. The square contains the chemical symbol for the element, the atomic number, and the atomic weight . The atomic weight of an element is a weighted average of its isotopes. |
Wave amplitude of a transverse wave is the difference in height between what and the resting position? | a magnitude | a valley | a cascade | a crest | Wave amplitude of a transverse wave is the difference in height between a crest and the resting position. Wave amplitude of a longitudinal wave is the distance between particles of the medium where it is compressed by the wave. |
What is secreted before ejaculation to neutralize acidic urine remaining in the urethra? | pre-cum | sperm | semen | clear mucus | |
Because conifers carry both male and female sporophylls on the same mature sporophyte, they are considered what type of plant? | dioecious | siliceous | bioecious | monoecious | Life Cycle of a Conifer Pine trees are conifers (cone bearing) and carry both male and female sporophylls on the same mature sporophyte. Therefore, they are monoecious plants. Like all gymnosperms, pines are heterosporous and generate two different types of spores: male microspores and female megaspores. In the male cones, or staminate cones, the microsporocytes give rise to pollen grains by meiosis. In the spring, large amounts of yellow pollen are released and carried by the wind. Some gametophytes will land on a female cone. Pollination is defined as the initiation of pollen tube growth. The pollen tube develops slowly, and the generative cell in the pollen grain divides into two haploid sperm cells by mitosis. At fertilization, one of the sperm cells will finally unite its haploid nucleus with the haploid nucleus of a haploid egg cell. Female cones, or ovulate cones, contain two ovules per scale. One megaspore mother cell, or megasporocyte, undergoes meiosis in each ovule. Three of the four cells break down; only a single surviving cell will develop into a female multicellular gametophyte, which encloses archegonia (an archegonium is a reproductive organ that contains a single large egg). Upon fertilization, the diploid egg will give rise to the embryo, which is enclosed in a seed coat of tissue from the parent plant. Fertilization and seed development is a long process in pine trees: it may take up to two years after pollination. The seed that is formed contains three generations of tissues: the seed coat that originates from the sporophyte tissue, the gametophyte that will provide nutrients, and the embryo itself. |
Who lack some of the defining traits of chordates? | Reptiles | Adult Mammals | Childern | adult humans | Adult humans lack some of the defining traits of chordates. Why are humans still classified in the chordate phylum?. |
What does convection within the earth's mantel cause? | microorganisms to move | volcanos | hurricanes | plates to move | Convection within the Earth’s mantle causes the plates to move. Mantle material is heated above the core. The hot mantle rises up towards the surface ( Figure below ). As the mantle rises it cools. At the surface the material moves horizontally away from a mid-ocean ridge crest. The material continues to cool. It sinks back down into the mantle at a deep sea trench. The material sinks back down to the core. It moves horizontally again, completing a convection cell. |
Autoimmunity can develop with time, and its causes may be rooted in this? | spontaneous mutation | inheritance | resistance | molecular mimicry | Autoimmunity can develop with time, and its causes may be rooted in molecular mimicry. Antibodies and TCRs may bind self antigens that are structurally similar to pathogen antigens, which the immune receptors first raised. As an example, infection with Streptococcus pyogenes (bacterium that causes strep throat) may generate antibodies or T cells that react with heart muscle, which has a similar structure to the surface of S. pyogenes. These antibodies can damage heart muscle with autoimmune attacks, leading to rheumatic fever. Insulin-dependent (Type 1) diabetes mellitus arises from a destructive inflammatory TH1 response against insulin-producing cells of the pancreas. Patients with this autoimmunity must be injected with insulin that originates from other sources. |
Why does warm air rise higher in the troposphere? | it is less flourishing than cool air | it is more dense than cool air | It contains hydrogen | it is less dense than cool air | Air in the troposphere is warmer closer to Earth’s surface. Warm air is less dense than cool air, so it rises higher in the troposphere. This starts a convection cell. Convection mixes the air in the troposphere. Rising air is also a main cause of weather. All of Earth’s weather takes place in the troposphere. |
Getting the same result when an experiment is repeated is called what? | repetition | mutation | initiation | replication | Scientists also have to “check their work. ” The results of an investigation are not likely to be well accepted unless the investigation is repeated—usually many times—and the same result is always obtained. Getting the same result when an experiment is repeated is called replication . If research results can be replicated, it means they are more likely to be correct. Repeated replication of investigations may turn a hypothesis into a theory. On the other hand, if results cannot be replicated they are likely to be incorrect. |
Some membranes have what kind of surfaces exposed to the cytoplasm? | bilayer | outer | obstructionary | hydrophobic | |
Plants and fungi cells have what basic cell structure, which animals do not have? | Cell Membrane | Cytoskeleton | Lysosomes | cell wall | Plants and fungi cells both have a cell wall, which animals do not have. |
The way in which the sun produces light is called what? | photosynthesis | tumescence | rays | incandescence | Most of the visible light on Earth comes from the sun. The sun and other stars produce light because they are so hot. They glow with light due to their extremely high temperatures. This way of producing light is called incandescence . Incandescent light bulbs also produce light in this way. When electric current passes through a wire filament inside an incandescent bulb, the wire gets so hot that it glows. Do you see the glowing filament inside the incandescent light bulb in the Figure below ?. |
What kind of light bulb contains a thin wire filament made of tungsten that gets hot and glows? | fluorescent | black light | LED | incandescent | An incandescent light bulb produces visible light by incandescence. The bulb contains a thin wire filament made of tungsten. When electric current passes through the filament, it gets extremely hot and glows. You can learn more about incandescent light bulbs at the URL below. |
What do you call a mixture in which some particles settle out of it when it is left standing? | homogenous | emulsion | alloy | suspension | A suspension is a heterogeneous mixture in which some of the particles settle out of the mixture upon standing. The particles in a suspension are far larger than those of a solution and thus gravity is able to pull them down out of the dispersion medium (water). The typical diameter for the dispersed particles (the sand) of a suspension is about 1000 times greater than those of a solution (less than approximately two nanometers for particles in solution, compared to greater than 1000 nanometers for particles in suspension). Unlike in a solution, the dispersed particles can be separated from the dispersion medium by filtering. Suspensions are heterogeneous because at least two different substances in the mixture can be identified. |
What do you call the process of a solid becoming a liquid? | freezing | boiling | vaporizing | melting | Substances can change phase—often because of a temperature change. At low temperatures, most substances are solid; as the temperature increases, they become liquid; at higher temperatures still, they become gaseous. The process of a solid becoming a liquid is called melting (an older term that you may see sometimes is fusion). The opposite process, a liquid becoming a solid, is called solidification. For any pure substance, the temperature at which melting occurs—known as the melting point—is a characteristic of that substance. It requires energy for a solid to melt into a liquid. Every pure substance has a certain amount of energy it needs to change from a solid to a liquid. This amount is called theenthalpy of fusion (or heat of fusion) of the substance, represented as ΔHfus. Some ΔHfus values are listed in Table 10.2 "Enthalpies of Fusion for Various Substances"; it is assumed that these values are for the melting point of the substance. Note that the unit of ΔHfus is kilojoules per mole, so we need to know the quantity of material to know how much energy is involved. The ΔHfus is always tabulated as a positive number. However, it can be used for both the melting and the solidification processes as long as you keep in mind that melting is always endothermic (so ΔH will be positive), while solidification is always exothermic (so ΔH will be negative). Table 10.2 Enthalpies of Fusion for Various Substances Substance (Melting Point). |
Once a plant cell becomes specialized, what can they no longer do? | osmosis | photosynthesis | cellular respiration | divide | As plant cells grow, they also become specialized into different cell types. Once cells become specialized, they can no longer divide. So how do plants grow after that? The key to continued growth is meristem. Meristem is a type of plant tissue consisting of undifferentiated cells that can continue to divide. |
The hardest natural substance, diamond is a form of what element? | hydrogen | zirconium | zenon | carbon | Diamond is a form of carbon in which each carbon atom is covalently bonded to four other carbon atoms. This forms a strong, rigid, three-dimensional structure (see Figure below ). Diamond is the hardest natural substance, and no other natural substance can scratch it. This property makes diamonds useful for cutting and grinding tools as well as for rings and other jewelry (see Figure below ). |
Much of what type of radiation that strikes the planet is reflected back into space? | microwaves | magentic radiation | gamma rays | solar radiation | |
What particles are formed from a neutron in beta decay? | atom and proton | rust and proton | mucus and a proton | electron and a proton | In beta decay, an electron and a proton form from a neutron (another unusual particle, called an antineutrino, is also produced). Only the electron is emitted from the nucleus. How does this change the atomic number and atomic mass of the atom?. |
What class of acids do carboxylic acids fall under? | carbolic acids | hydrochloric acids | inorganic acids | organic acids | Common acids and the polyatomic anions derived from them have their own names and rules for nomenclature. The nomenclature of acids differentiates between oxoacids, in which the H+ ion is attached to an oxygen atom of a polyatomic ion, and acids in which the H + ion is attached to another element. Carboxylic acids are an important class of organic acids. Ammonia is an important base, as are its organic derivatives, the amines. |
Plants can absorb inorganic nutrients and water through their root system, and what gas from the environment? | chemical dioxide | hydrogen dioxide | nitrogen dioxide | carbon dioxide | CHAPTER SUMMARY 31.1 Nutritional Requirements of Plants Plants can absorb inorganic nutrients and water through their root system, and carbon dioxide from the environment. The combination of organic compounds, along with water, carbon dioxide, and sunlight, produce the energy that allows plants to grow. Inorganic compounds form the majority of the soil solution. Plants access water though the soil. Water is absorbed by the plant root, transports nutrients throughout the plant, and maintains the structure of the plant. Essential elements are indispensable elements for plant growth. They are divided into macronutrients and micronutrients. The macronutrients plants require are carbon, nitrogen, hydrogen, oxygen, phosphorus, potassium, calcium, magnesium, and sulfur. Important micronutrients include iron, manganese, boron, molybdenum, copper, zinc, chlorine, nickel, cobalt, silicon and sodium. |
Giardia is an example of a protozoa that uses flagella for what purpose? | light | reproduction | nutrients | movement | type of protozoa, such as Giardia, that moves with flagella. |
Nearly all earthquakes occur where? | in large cities | plate centers | in Asia | plate boundaries | Nearly all earthquakes occur at plate boundaries, and all types of plate boundaries have earthquakes. |
Conotoxins released by certain marine snails can bring about paralysis in humans, indicating that this toxin attacks what system? | cardiovascular | cerebral | circulatory | neurological | Can Snail Venom Be Used as a Pharmacological Painkiller? Marine snails of the genus Conus (Figure 28.25) attack prey with a venomous sting. The toxin released, known as conotoxin, is a peptide with internal disulfide linkages. Conotoxins can bring about paralysis in humans, indicating that this toxin attacks neurological targets. Some conotoxins have been shown to block neuronal ion channels. These findings have led researchers to study conotoxins for possible medical applications. Conotoxins are an exciting area of potential pharmacological development, since these peptides may be possibly modified and used in specific medical conditions to inhibit the activity of specific neurons. For example, these toxins may be used to induce paralysis in muscles in specific health applications, similar to the use of botulinum toxin. Since the entire spectrum of conotoxins, as well as their mechanisms of action, are not completely known, the study of their potential applications is still in its infancy. Most research to date has focused on their use to treat neurological diseases. They have also shown some efficacy in relieving chronic pain, and the pain associated with conditions like sciatica and shingles. The study and use of biotoxins—toxins derived from living organisms—are an excellent example of the application of biological science to modern medicine. |
What is the second largest planet in the solar system? | Mars | Venus | jupiter | saturn | Saturn is the second largest planet in the solar system ( Figure below ). Saturn’s mass is about 95 times Earth's mass. The gas giant is 755 times Earth’s volume. Despite its large size, Saturn is the least dense planet in our solar system. Saturn is actually less dense than water. This means that if there were a bathtub big enough, Saturn would float! In Roman mythology, Saturn was the father of Jupiter. Saturn orbits the Sun once about every 30 Earth years. |
Fruit comes from the ovaries of what types of plants? | sprouting | deciduous | perennial | flowering | Although flowers and their components are the major innovations of angiosperms, they are not the only ones. Angiosperms also have more efficient vascular tissues. Additionally, in many flowering plants the ovaries ripen into fruits. Fruits are often brightly colored, so animals are likely to see and eat them and disperse their seeds (see Figure below ). |
Resistors connected end to end are said to be in what? | lines | parallel | groups | series | Resistors in Series: All resistors are connected end to end. There is only one river, so they all receive the same current. But since there is a voltage drop across each resistor, they may all have different voltages across them – the sum of the voltage drops will equal the total voltage of the circuit. The more resistors in series the more rocks in the river, so the less current that flows. |
Molar mass is equal to density multiplied by what? | molar gravity | molar energy | molar weight | molar volume | Molar mass is equal to density multiplied by molar volume. |
What plastid makes and stores other pigments? | sporozoans | pores | pores | chromoplasts | Chromoplasts are plastids that make and store other pigments. The red pigment that colors the flower petals in Figure above was made by chromoplasts. |
What effect causes global winds to blow on a diagonal over the earth's surface? | centrifugal effect | dopler effect | resonant effect | coriolis effect | Global winds occur in belts around the globe. They are caused by unequal heating of Earth’s surface. The Coriolis effect causes global winds to blow on a diagonal over the surface. Unequal heating also causes jet streams high in the troposphere. |
When members of the same species compete for the same resources, it is called what? | extinction | interspecies competition | natural selection | intraspecific competition | Intraspecific competition happens when members of the same species compete for the same resources. For example, two trees may grow close together and compete for light. One may out-compete the other by growing taller to get more available light. As members of the same species are usually genetically different, they have different characteristics, and in this example, one tree grows taller than the other. The organism that is better adapted to that environment is better able to survive. The other organism may not survive. In this example, it is the taller tree that is better adapted to the environment. |
Antibiotics only target prokaryotic cells - they do not affect fungi, which are not prokaryotic, but instead what? | plants | chloroplasts | mammals | eukaryotic | Animal and Human Parasites and Pathogens Fungi can affect animals, including humans, in several ways. Fungi attack animals directly by colonizing and destroying tissues. Humans and other animals can be poisoned by eating toxic mushrooms or foods contaminated by fungi. In addition, individuals who display hypersensitivity to molds and spores develop strong and dangerous allergic reactions. Fungal infections are generally very difficult to treat because, unlike bacteria, fungi are eukaryotes. Antibiotics only target prokaryotic cells, whereas compounds that kill fungi also adversely affect the eukaryotic animal host. Many fungal infections ( mycoses) are superficial and termed cutaneous (meaning “skin”) mycoses. They are usually visible on the skin of the animal. Fungi that cause the superficial mycoses of the epidermis, hair, and nails rarely spread to the underlying tissue (Figure 13.26). These fungi are often misnamed “dermatophytes” from the Greek dermis skin and phyte plant, but they are not plants. Dermatophytes are also called “ringworms” because of the red ring that they cause on skin (although the ring is caused by fungi, not a worm). These fungi secrete extracellular enzymes that break down keratin (a protein found in hair, skin, and nails), causing a number of conditions such as athlete’s foot, jock itch, and other cutaneous fungal infections. These conditions are usually treated with over-the-counter topical creams and powders, and are easily cleared. More persistent, superficial mycoses may require prescription oral medications. |
What do bees carry from one plant to another to facilitate plant growth and development? | fungi | nutrients | spores | pollen | Bees are beautiful creatures that help plants flourish. They carry pollen from one plant to another to facilitate plant growth and development. But, they can also be troublesome when they sting you. For people who are allergic to bee venom, this can be a serious, life-threatening problem. For the rest of us, it can be a painful experience. When stung by a bee, one first-aid treatment is to apply a paste of baking soda (sodium bicarbonate) to the stung area. This weak base helps with the itching and swelling that accompanies the bee sting. |
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