questions stringlengths 37 1.22k | reasoning stringlengths 0 3.56k ⌀ | answers stringlengths 4 138 |
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Flow of what can introduce alleles that are advantageous or ones that are disadvantageous?
Here are the choices:
A. genes
B. larvae
C. babies
D. eggs | A: genes. | |
A life cycle continues through reproduction and what?
Here are the choices:
A. development
B. mechanical
C. response
D. example | A: development. | |
Bacteria are like eukaryotic cells in that they have cytoplasm, ribosomes, and a?
Here are the choices:
A. brain
B. cell wall
C. plasma membrane
D. chloroplast | Bacteria are like eukaryotic cells in that they have cytoplasm, ribosomes, and a plasma membrane. | C: plasma membrane. |
When zinc metal is mixed with sulfur and heated, what is produced?
Here are the choices:
A. methane sulfide
B. extraction sulfide
C. zinc sulfide
D. iron | 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. | C: zinc sulfide. |
What cage composed of 12 pairs of ribs, with their costal cartilages and the sternum, protects the heart and lungs?
Here are the choices:
A. thoracic
B. sacral
C. lumbar
D. cervical | 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. | A: thoracic. |
What is the ability of an atom to emit charged particles and energy from its nucleus called?
Here are the choices:
A. power
B. accumulation
C. conductivity
D. 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. | D: radioactivity. |
Diffusion is an effective transport mechanism over the spatial scales typically found at what level?
Here are the choices:
A. molecular
B. atom
C. electromagnetic
D. cellular | D: cellular. | |
In a car race on a circular track, where the start and finish line are the same, what quantity is neglible?
Here are the choices:
A. total distance
B. total displacement
C. total acceleration
D. partial 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. | B: total displacement. |
What is another name for molecular compounds?
Here are the choices:
A. oxidized compounds
B. synthetic compounds
C. covalent compounds
D. phenotype 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. | C: covalent compounds. |
The long mouth-tube that some insects use to suck up the nectar of the flower is called what?
Here are the choices:
A. stamen
B. pistil
C. prosthesis
D. 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. | D: proboscis. |
Cnvs result from regions of what being duplicated or deleted inconsistently within the population?
Here are the choices:
A. cytoplasm
B. genome
C. DNA
D. genes | B: genome. | |
Insects can have specialized mouthparts, such as a proboscis, to siphon the nectar from what?
Here are the choices:
A. fruits
B. flowers
C. stems
D. shrubs | Insects can have specialized mouthparts, such as a proboscis, to siphon the nectar from a flower. | B: flowers. |
What is the invisible force that pulls things to earth?
Here are the choices:
A. electromagnetism
B. momentum
C. gravity
D. motion | 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?. | C: gravity. |
What do we call the seasonal movement of animals?
Here are the choices:
A. population
B. immigration
C. migration
D. trade | 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. | C: migration. |
What kind of beneficial relationships with other organisms are common in the plant kingdom?
Here are the choices:
A. autotrophic
B. mutualistic
C. symbiotic
D. Host | B: mutualistic. | |
Some marine algae have evolved special structures capable of what plant process?
Here are the choices:
A. seed germination
B. pollination
C. respiration
D. 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. | D: photosynthesis. |
What is the substance called whenatoms of different elements join together?
Here are the choices:
A. crusts
B. plants
C. crystals
D. 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. | D: compounds. |
What type of solid has atoms arranged in a repeating pattern?
Here are the choices:
A. crystals
B. hydrocarbons
C. metals
D. ions | 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. | A: crystals. |
What is the process called when secretory cells export products?
Here are the choices:
A. isolation
B. exocytosis
C. morphogenesis
D. endocytosis | B: exocytosis. | |
Natural resources that are limited in supply and cannot be replaced except over millions of years are known as what?
Here are the choices:
A. biological
B. nonrenewable
C. renewable
D. precious | 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. | B: nonrenewable. |
What is a hydrocarbon in which the carbon chain joins to itself in a ring?
Here are the choices:
A. asymmetrical hydrocarbon
B. acid hydrocarbon
C. circular hydrocarbon
D. 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. | D: cyclic hydrocarbon. |
The first photosynthetic organisms were not plants, but types of what that lived in the water?
Here are the choices:
A. bacteria
B. algae
C. pathogens
D. fungi | 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?. | A: bacteria. |
What is the second stage of photosynthesis?
Here are the choices:
A. production of glucose
B. pigment release
C. glucose destruction
D. production of protein | 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. | A: production of glucose. |
Which layer is the lithosphere located?
Here are the choices:
A. outermost layer
B. radii layer
C. eclipses layer
D. nearest 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. | A: outermost layer. |
What is speed at any given instant called?
Here are the choices:
A. relative speed
B. marginal speed
C. spontaneous speed
D. 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. | D: instantaneous speed. |
During birth, a baby passes from the uterus through what organ to leave the body?
Here are the choices:
A. Esophagus
B. the urethra
C. the vagina
D. Ovary | 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. | C: the vagina. |
What type of earthquake creates a tsunami?
Here are the choices:
A. underwater
B. Tectonic
C. collapse
D. volcanic | 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. | A: underwater. |
What is the smallest of the galilean moons?
Here are the choices:
A. demos
B. aura
C. phoebe
D. 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. | D: europa. |
What is the term for a combination of substances in which there is no chemical reaction?
Here are the choices:
A. a combination
B. a solute
C. a mixture
D. a solution | 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. | C: a mixture. |
Where does the majority of chemical digestion occur?
Here are the choices:
A. stomach
B. large intestine
C. mouth
D. 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. | D: small intestine. |
The vertebrate endoskeleton includes a vertebral column, cranium, limbs, and what else?
Here are the choices:
A. limb girdles
B. blood girdles
C. tissue girdles
D. Skin 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?. | A: limb girdles. |
What is defined as the velocity of the object at a given moment?
Here are the choices:
A. relativistic velocity
B. specific gravity
C. inertia
D. 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. | D: instantaneous velocity. |
What is the term for an expression showing the relationship of the reaction rate to the concentrations of each reactant?
Here are the choices:
A. rate law
B. concentric law
C. flow law
D. decay 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. | A: rate law. |
How many pi bonds are found in a triple bond?
Here are the choices:
A. 10
B. four
C. two
D. six | From the stirrup, the vibrations pass to the oval window . This is another membrane like the eardrum. | C: two. |
What is formed when an acidic solution and a basic solution react together in a neutralization reaction?
Here are the choices:
A. shallow
B. Sodium
C. salt
D. seawater | An acidic solution and a basic solution react together in a neutralization reaction that also forms a salt. | C: salt. |
What is the causative agent of sleeping sickness in humans?
Here are the choices:
A. bacillus aerophilus
B. trypanosoma brucei
C. pseudomonas asplenii
D. escherichia coli | 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). | B: trypanosoma brucei. |
Living things that use energy to make food, both for themselves and other living things, are what part of an ecosystem?
Here are the choices:
A. decomposers
B. growers
C. consumers
D. 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:. | D: producers. |
In science, what process produces evidence that helps answer questions and solve problems?
Here are the choices:
A. investigation
B. information
C. suspension
D. manipulation | 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. | A: investigation. |
What cellular structure is used during endocytosis to allow molecules to enter the cell?
Here are the choices:
A. tissues
B. vesicles
C. membranes
D. nucleus | B: vesicles. | |
What are unique about prokaryotic cells' organelles?
Here are the choices:
A. only membrane - bound
B. no cell walls
C. no epidermis
D. 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. | D: not membrane-bound. |
How long ago did the ancestors of mammals evolve?
Here are the choices:
A. 50,900 million years
B. 300 million years
C. 100 million
D. 10 million | 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. | B: 300 million years. |
A d. melanogaster population has an average heterozygosity of what?
Here are the choices:
A. 22 %
B. 14%
C. 21 %
D. 19 % | B: 14%. | |
Traits that are affected by more than one gene are what type of traits?
Here are the choices:
A. monogenetic
B. recessive
C. polygenic traits
D. dominant | 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. | C: polygenic traits. |
Pharmacist and surveyor are two career options based in what type of science?
Here are the choices:
A. Business
B. visible
C. obvious
D. physical | There are many career options in physical science. Examples include pharmacist and surveyor. | D: physical. |
What is another term for foodborne illness?
Here are the choices:
A. food poisoning
B. pathogen
C. cancer
D. disease | 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. | A: food poisoning. |
The mechanical advantage of a machine is related to how it changes what?
Here are the choices:
A. force
B. pressure
C. nature
D. example | The mechanical advantage of a machine is related to how it changes force. Explain this relationship. | A: force. |
What term in physics refers to the use of force to move an object?
Here are the choices:
A. mass
B. work
C. velocity
D. momentum | 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. | B: work. |
What is the name of the organelle that helps make and transport proteins and lipids?
Here are the choices:
A. plasma membrane
B. endoplasmic reticulum
C. mitochondria
D. nucleus | 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. | B: endoplasmic reticulum. |
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?
Here are the choices:
A. alethiometer
B. calorimeter
C. radio telescope
D. thermometer | 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. | B: calorimeter. |
What is the name of the outer part of the adrenal gland located above the kidneys?
Here are the choices:
A. nucleus
B. cortex
C. mitochondria
D. spleen | 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. | B: cortex. |
What kind of energy used heat from magma within the earth to heat homes or produce steam that turns turbines?
Here are the choices:
A. thermal energy
B. robust energy
C. renewable energy
D. geothermal energy | Geothermal energy uses heat from magma within the Earth to heat homes or produce steam that turns turbines. | D: geothermal energy. |
The primary output of the basal nuclei is to the thalamus, which relays that output to where?
Here are the choices:
A. effect cortex
B. cerebral cortex
C. suffering cortex
D. Back 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. | B: cerebral cortex. |
The central nervous system is composed of the brain and what else?
Here are the choices:
A. the lateral cord
B. the sclerotic cord
C. the spinal cord
D. the dynamic 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. | C: the spinal cord. |
A group of genetically identical individuals is called what?
Here are the choices:
A. a clone
B. replicant
C. brother
D. a man | A: a clone. | |
Where on the earth's surface does the water cycle takes place?
Here are the choices:
A. on , below , and below
B. for , above , and below
C. on, above, and below
D. inside,under,above | 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. | C: on, above, and below. |
Under which conditions do many bacteria carry out alcohol fermentation?
Here are the choices:
A. photosynthesis
B. melting
C. enzymatic
D. anaerobic | D: anaerobic. | |
Fermat's principle states that what will always take the path that takes the least amount of time?
Here are the choices:
A. light
B. sound
C. electricity
D. wind | 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). | A: light. |
What trend is occurring involving the extent of arctic sea ice in summer?
Here are the choices:
A. water decrease
B. Ice growth
C. slow decrease
D. 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. | D: rapid decrease. |
In vertebrates, cholesterol is synthesized in which organ and obtained from the diet?
Here are the choices:
A. the bone
B. the liver
C. the brain
D. heart | B: the liver. | |
What is a group of lions called?
Here are the choices:
A. bevy
B. coven
C. pride
D. herd | 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. | C: pride. |
Which layer is found below the lithosphere?
Here are the choices:
A. asthenosphere
B. magnetosphere
C. troposphere
D. stratosphere | 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. | A: asthenosphere. |
What is the name for the nonliving parts of ecosystems?
Here are the choices:
A. nucleic factors
B. diverse factors
C. Dead factors
D. 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. | D: abiotic factors. |
What do you call the electrons in the outermost energy level of an atom?
Here are the choices:
A. Proper electrons
B. shell electrons
C. Inner electrons
D. 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. | D: valence electrons. |
What are some of the giant fairy rings produced by?
Here are the choices:
A. algae
B. sporangia
C. fronds
D. mycelia | D: mycelia. | |
What are ingrowths on arthropod exoskeletons to which muscles attach?
Here are the choices:
A. apodemes
B. joints
C. rods
D. pores | 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. | A: apodemes. |
Which type of electrons plays the most important role in chemical reactions?
Here are the choices:
A. noncovalent
B. intermediate
C. transition
D. 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. | D: valence. |
What level is greater than 7 in a basic solution?
Here are the choices:
A. uh
B. ph
C. fh
D. gh | 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. | B: ph. |
What happens to volume as the temperature increases?
Here are the choices:
A. volume is unchanged
B. volume decreases
C. volume increases
D. volume fluctuates | The volume increases as the temperature increases. The result has three significant figures. | C: volume increases. |
What does an array of radio telescopes collect?
Here are the choices:
A. microwaves
B. light waves
C. radio waves
D. thermal waves | Radio telescopes collect radio waves and are sometimes used in large arrays. | C: radio waves. |
What kind of compounds contain positively and negatively charged ions in a ratio that results in an overall charge of zero?
Here are the choices:
A. neutral compounds
B. zero charged compunds
C. zeronic ions
D. 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. | D: ionic compounds. |
What are formed when crystals precipitate out from a liquid?
Here are the choices:
A. chemical sedimentary rocks
B. additive sedimentary rocks
C. gaseous sedimentary rocks
D. diamonds | 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 ). | A: chemical sedimentary rocks. |
Roundworms exemplify what type of organization, where two or more types of tissues work together to perform a particular function as an organ?
Here are the choices:
A. organ-level organization
B. delicate - level organization
C. bone-level organization
D. land-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. | A: organ-level organization. |
Where are protons and neutrons located?
Here are the choices:
A. electron shell
B. radius
C. epidermis
D. 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. | D: nucleus. |
Why do hummingbirds have long narrow bills?
Here are the choices:
A. for protection against predators
B. to reach the nectar at the bottom of flowers
C. to store food
D. to feed their offspring | dome-shaped plug of thick lava that cools near the vent of a volcano. | B: to reach the nectar at the bottom of flowers. |
Bivalvia and gastropoda are classes of what phylum?
Here are the choices:
A. fishes
B. mollusks
C. diatoms
D. Insects | 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. | B: mollusks. |
Kinetic energy of moving particles of matter, measured by their temperatures are known as:
Here are the choices:
A. thermal energy
B. visible energy
C. solar energy
D. atmospheric 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:. | A: thermal energy. |
What is the term for a process that changes some chemical substances into others?
Here are the choices:
A. chain reaction
B. chemical reaction
C. toxic reaction
D. acid 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. | B: chemical reaction. |
The diagnosis of a disease or condition before the baby is born is called?
Here are the choices:
A. prenatal diagnosis
B. specialized diagnosis
C. immature diagnosis
D. specific diaganosis | A: prenatal diagnosis. | |
A heterogeneous mixture of particles of one substance distributed throughout a second substance in a different phase is known as what?
Here are the choices:
A. suspension
B. disruption
C. solution
D. fluid | Summary A suspension is a heterogeneous mixture of particles of one substance distributed throughout a second phase; the dispersed particles separate from the dispersing phase on standing. In contrast, the particles in a colloid are smaller and do not separate on standing. A colloid can be classified as a sol, a dispersion of solid particles in a liquid or solid; a gel, a semisolid sol in which all of the liquid phase has been absorbed by the solid particles; an aerosol, a dispersion of solid or liquid particles in a gas; or an emulsion, a dispersion of one liquid phase in another. A colloid can be distinguished from a true solution by its ability to scatter a beam of light, known as the Tyndall effect. Hydrophilic colloids contain an outer shell of groups that interact favorably with water, whereas hydrophobic colloids have an outer surface with little affinity for water. Emulsions are prepared by dispersing a hydrophobic liquid in water. In the absence of a dispersed hydrophobic liquid phase, solutions of detergents in water form organized spherical aggregates calledmicelles. Phospholipids are a class of detergent-like molecules that have two Saylor URL: http://www. saylor. org/books. | A: suspension. |
On what type of land does runoff cause more erosion?
Here are the choices:
A. bare
B. grassy
C. mountainous
D. metallic | Runoff causes more erosion if the land is bare. Plants help hold the soil in place. The runoff water pictured below ( Figure below ) is brown because it eroded soil from a bare, sloping field. Can you find evidence of erosion by runoff where you live? What should you look for?. | A: bare. |
What kind of fats have been implicated in the presence of heart disease?
Here are the choices:
A. animal fats
B. plant fats
C. key fats
D. trans fats | linked to a lower incidence of certain diseases. Thus, there have been an increasing number of recommendations by government bodies and health associations to decrease the proportion of saturated fat and increase the proportion of unsaturated fat in the diet. Most of these organizations also recommend decreasing the total amount of fat in the diet. Recently, certain fats called trans fats have been implicated in the presence of heart disease. These are fats from animal sources and are also produced when liquid oils are exposed to partial hydrogenation, an industrial process that increases their saturation. Trans fats are used in many prepared and fried foods. Because they bring with them the health risks that naturally occurring saturated fats do, there has been some effort to better quantify the presence of trans fats in food products. US law now requires that food labels list the amount of trans fat in each serving. Since 1992, the US Department of Agriculture has been promoting a food pyramid that gives a simple, visual picture of how much of what kind of foods make up a good, balanced diet. It recommends eating as few fats as possible. Although nutritionists recognize that some fat is necessary (and largely unavoidable, even by strict vegetarians), they emphasize that a large proportion of any fat, saturated or unsaturated, in the diet is unhealthy. Even so, a difference as simple as the difference between a single and double carbon–carbon bond can have a significant impact on health. | D: trans fats. |
Inducible enzymes usually function in what type of pathways?
Here are the choices:
A. biogenic
B. catabolic
C. anabolic
D. enzymatic | B: catabolic. | |
Since electrons are charged, their intrinsic spin creates a what?
Here are the choices:
A. intrinsic magnetic field
B. intrinsic electrical field
C. suppressed electrical field
D. magnified rupulsed field | We already know that the magnitude of angular momentum is quantized for electron orbits in atoms. The new insight is that the direction of the orbital angular momentum is also quantized. The fact that the orbital angular momentum can have only certain directions is called space quantization. Like many aspects of quantum mechanics, this quantization of direction is totally unexpected. On the macroscopic scale, orbital angular momentum, such as that of the moon around the earth, can have any magnitude and be in any direction. Detailed treatment of space quantization began to explain some complexities of atomic spectra, but certain patterns seemed to be caused by something else. As mentioned, spectral lines are actually closely spaced doublets, a characteristic called fine structure, as shown in Figure 30.53. The doublet changes when a magnetic field is applied, implying that whatever causes the doublet interacts with a magnetic field. In 1925, Sem Goudsmit and George Uhlenbeck, two Dutch physicists, successfully argued that electrons have properties analogous to a macroscopic charge spinning on its axis. Electrons, in fact, have an internal or intrinsic angular momentum called intrinsic spin S . Since electrons are charged, their intrinsic spin creates an intrinsic magnetic field. | A: intrinsic magnetic field. |
What do bats use to determine the location of objects?
Here are the choices:
A. echolocation
B. syncopation
C. UV light
D. infrared light | Christopher Auyeung, using bat image by User:Rugby471/Wikimedia Commons. Bats use echolocation to identify the location of objects . CC BY-NC 3.0 (bat image available under public domain). | A: echolocation. |
Caffeine is an example of what type of drug?
Here are the choices:
A. nicotine
B. barbiturate
C. psychoactive
D. depressant | diploid spore in fungi that is produced by the fusion of two haploid parent cells. | C: psychoactive. |
What is the use of technology to change the genetic makeup of living things for human purposes?
Here are the choices:
A. genetic employing
B. biological utility
C. genetic engineering
D. biological engineering | Treating genetic disorders is one use of biotechnology. Biotechnology is the use of technology to change the genetic makeup of living things for human purposes. It's also called genetic engineering. Besides treating genetic disorders, biotechnology is used to change organisms so they are more useful to people. | C: genetic engineering. |
What distinctive configuration of dna demonstrates the base-pairing nature of the bases?
Here are the choices:
A. single helix
B. double loop
C. triple helix
D. double helix | The double helical nature of DNA, together with the findings of Chargaff, demonstrated the base-pairing nature of the bases. Adenine always pairs with thymine, and guanine always pairs with cytosine ( Figure below ). Because of this complementary nature of DNA, the bases on one strand determine the bases on the other strand. These complementary base pairs explain why the amounts of guanine and cytosine are present in equal amounts, as are the amounts of adenine and thymine. Adenine and guanine are known as purines . These bases consist of two ring structures. Purines make up one of the two groups of nitrogenous bases. Thymine and cytosine are pyrimidines , which have just one ring structure. By having a purine always combine with a pyrimidine in the DNA double helix, the distance between the two sugar-phosphate backbones is constant, maintaining the uniform shape of the DNA molecule. | D: double helix. |
Lipids are broken down by what?
Here are the choices:
A. amino acids
B. hydrolysis
C. lipases
D. triglycerides | Dehydration and hydrolysis reactions are catalyzed, or “sped up,” by specific enzymes; dehydration reactions involve the formation of new bonds, requiring energy, while hydrolysis reactions break bonds and release energy. These reactions are similar for most macromolecules, but each monomer and polymer reaction is specific for its class. For example, in our bodies, food is hydrolyzed, or broken down, into smaller molecules by catalytic enzymes in the digestive system. This allows for easy absorption of nutrients by cells in the intestine. Each macromolecule is broken down by a specific enzyme. For instance, carbohydrates are broken down by amylase, sucrase, lactase, or maltase. Proteins are broken down by the enzymes pepsin and peptidase, and by hydrochloric acid. Lipids are broken down by lipases. Breakdown of these macromolecules provides energy for cellular activities. | C: lipases. |
What are considered to be the most basic concepts in the field of physical science?
Here are the choices:
A. change and energy
B. energy and motion
C. force and matter
D. matter and energy | Matter and energy are the most basic concepts in physical science. Watch this video about matter and energy, and then answer the questions below. | D: matter and energy. |
What are materials that can be magnetized called?
Here are the choices:
A. ferromagnetic materials
B. interstitial materials
C. catalytic materials
D. Metal material | Only certain materials, called ferromagnetic materials, can be magnetized. They include iron, cobalt, and nickel. Materials that have been magnetized may become temporary or permanent magnets. | A: ferromagnetic materials. |
Toxic compounds in the environment have the most severe impact on animals that are top-level what?
Here are the choices:
A. omnivores
B. vegetarian
C. herbivores
D. carnivores | D: carnivores. | |
In genetics, what do you call characteristics that are passed from a parent to child?
Here are the choices:
A. traits
B. similarities
C. mutations
D. habits | A: traits. | |
One gram of proteins provides how many calories of energy?
Here are the choices:
A. two
B. zero
C. four
D. eight | Dietary proteins are broken down during digestion to provide the amino acids needed for protein synthesis. Any extra proteins in the diet not needed for this purpose are used for energy or stored as fat. One gram of proteins provides 4 Calories of energy. | C: four. |
What kind of succession occurs in an area that has never before been colonized?
Here are the choices:
A. primary succession
B. support succession
C. addition succession
D. secondary succession | Primary succession occurs in an area that has never before been colonized. Pioneer species include bacteria and lichens that can grow on bare rock and help make soil. | A: primary succession. |
A sprain is a strain or tear in what part of the body?
Here are the choices:
A. a ligament
B. torso
C. stomach
D. skeleton | Another type of skeletal system injury is a sprain. A sprain is a strain or tear in a ligament that has been twisted or stretched too far. Ankle sprains are a common type of sprain. Athletes often strain a ligament in the knee called the ACL. Warming up adequately and stretching before playing sports may reduce the risk of a sprain. Ligament injuries can take a long time to heal. Rest, ice, compression, and elevation of the sprained area may help the healing process. | A: a ligament. |
Which gland is located in the sella turcica of the sphenoid bone within the cranial floor?
Here are the choices:
A. pituitary gland
B. mammalian gland
C. glucose gland
D. thyroid gland | Figure 16.8 Pituitary Tumor The pituitary gland is located in the sella turcica of the sphenoid bone within the cranial floor, placing it immediately inferior to the optic chiasm. If the pituitary gland develops a tumor, it can press against the fibers crossing in the chiasm. Those fibers are conveying peripheral visual information to the opposite side of the brain, so the patient will experience “tunnel vision”—meaning that only the central visual field will be perceived. | A: pituitary gland. |
What is light that has only a single wavelength called?
Here are the choices:
A. primary
B. spectroscopy
C. fluorescent
D. monochromatic | with only certain radii were allowed. Lines in the spectrum were due to transitions in which an electron moved from a higher-energy orbit with a larger radius to a lower-energy orbit with smaller radius. The orbit closest to the nucleus represented theground state of the atom and was most stable; orbits farther away were higher-energy excited states. Transitions from an excited state to a lower-energy state resulted in the emission of light with only a limited number of wavelengths. Bohr’s model could not, however, explain the spectra of atoms heavier than hydrogen. Most light is polychromatic and contains light of many wavelengths. Light that has only a single wavelength is monochromatic and is produced by devices called lasers, which use transitions between two atomic energy levels to produce light in a very narrow range of wavelengths. Atoms can also absorb light of certain energies, resulting in a transition from the ground state or a lower-energy excited state to a higher-energy excited state. This produces an absorption spectrum, which has dark lines in the same position as the bright lines in the emission spectrum of an element. | D: monochromatic. |
Combined substances are either compounds or what?
Here are the choices:
A. solutions
B. concentrations
C. combinations
D. mixtures | Ahhhh! A tall glass of ice-cold lemonade is really refreshing on a hot day. Lemonade is a combination of lemon juice, water, and sugar. Do you know what kind of matter lemonade is? It’s obviously not an element because it consists of more than one substance. Is it a compound? Not all combined substances are compounds. Some—including lemonade—are mixtures. | D: mixtures. |
What are the catalysts that occur naturally in living organisms and are primarily protein molecules?
Here are the choices:
A. hormones
B. acids
C. enzymes
D. carbohydrates | Enzymes Enzymes, catalysts that occur naturally in living organisms, are almost all protein molecules with typical molecular masses of 20,000–100,000 amu. Some are homogeneous catalysts that react in aqueous solution within a cellular compartment of an organism. Others are heterogeneous catalysts embedded within the membranes that separate cells and cellular compartments from their surroundings. The reactant in an enzyme-catalyzed reaction is called a substrate. Because enzymes can increase reaction rates by enormous factors (up to 10 17 times the uncatalyzed rate) and tend to be very specific, typically producing only a single product in quantitative yield, they are the focus of active research. At the same time, enzymes are usually expensive to obtain, they often cease functioning at temperatures greater than 37°C, have limited stability in solution, and have such high specificity that they are confined to turning one particular set of reactants into one particular product. This means that separate processes using different enzymes must be developed for chemically similar reactions, which is time-consuming and expensive. Thus far, enzymes have found only limited industrial applications, although they are used as ingredients in laundry detergents, contact lens cleaners, and meat tenderizers. The enzymes in these applications tend to be proteases, which are able to cleave the amide bonds that hold amino acids together in proteins. Meat tenderizers, for example, contain a protease called papain, which is isolated from papaya juice. It cleaves some of the long, fibrous protein molecules that make inexpensive cuts of beef tough, producing a piece of meat that is more tender. Some insects, like the bombadier beetle, carry an enzyme capable of catalyzing the decomposition of hydrogen peroxide to water (Figure 14.28 "A Catalytic Defense Mechanism"). Enzyme inhibitors cause a decrease in the reaction rate of an enzyme-catalyzed reaction by binding to a specific portion of an enzyme and thus slowing or preventing a reaction from occurring. Irreversible inhibitors are therefore the equivalent of poisons in heterogeneous catalysis. One of the oldest and most Saylor URL: http://www. saylor. org/books. | C: enzymes. |
Amino acid units in a protein are connected by what bonds?
Here are the choices:
A. covalent
B. ionic
C. acidic
D. peptide | Amino acid units in a protein are connected by peptide bonds. What is another name for the functional group linking the amino acids?. | D: peptide. |
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