Split (1)

test · 389k rows

questions stringlengths 37 1.22k	reasoning stringlengths 0 3.56k ⌀	answers stringlengths 4 138
What blood component serves both structural and molecular functions in blood clotting? Here are the choices: A. plasma B. proteins C. platelets D. molecules		C: platelets.
What type of reproduction begins when an egg and sperm combine? Here are the choices: A. natural reproduction B. sexual reproduction C. regular reproduction D. asexual reproduction	18.1 How Animals Reproduce Reproduction may be asexual when one individual produces genetically identical offspring, or sexual when the genetic material from two individuals is combined to produce genetically diverse offspring. Asexual reproduction in animals occurs through fission, budding, fragmentation, and parthenogenesis. Sexual reproduction may involve fertilization inside the body or in the external environment. A species may have separate sexes or combined sexes; when the sexes are combined they may be expressed at different times in the life cycle. The sex of an individual may be determined by various chromosomal systems or environmental factors such as temperature. Sexual reproduction starts with the combination of a sperm and an egg in a process called fertilization. This can occur either outside the bodies or inside the female. The method of fertilization varies among animals. Some species release the egg and sperm into the environment, some species retain the egg and receive the sperm into the female body and then expel the developing embryo covered with shell, while still other species retain the developing offspring throughout the gestation period.	B: sexual reproduction.
What are long chains of amino acids? Here are the choices: A. cells B. Fatty Acid Chains C. proteins D. lipids	The reverse reaction (amide hydrolysis) is very useful in the study of protein structure. Proteins are long chains of amino acids (each amino acid contains an amine group and a carboxyl group, both attached to a central carbon atom). The amino acids are linked together by amide bonds to form the long protein chain. One of the techniques for looking at protein structure is to break those amide linkages so we can learn the identity of the amino acids in the chain. We do this through a hydrolysis reaction:.	C: proteins.
What phase exists when all the water in a container has physical properties intermediate between those of the gaseous and liquid states? Here are the choices: A. impregnation fluid B. hydrothermal fluid C. supercritical fluid D. stationary fluid	Supercritical Fluids If we place a sample of water in a sealed container at 25 °C, remove the air, and let the vaporization-condensation equilibrium establish itself, we are left with a mixture of liquid water and water vapor at a pressure of 0.03 atm. A distinct boundary between the more dense liquid and the less dense gas is clearly observed. As we increase the temperature, the pressure of the water vapor increases, as described by the liquid-gas curve in the phase diagram for water (Figure 10.31), and a two-phase equilibrium of liquid and gaseous phases remains. At a temperature of 374 °C, the vapor pressure has risen to 218 atm, and any further increase in temperature results in the disappearance of the boundary between liquid and vapor phases. All of the water in the container is now present in a single phase whose physical properties are intermediate between those of the gaseous and liquid states. This phase of matter is called a supercritical fluid, and the temperature and pressure above which this phase exists is the critical point (Figure 10.35). Above its critical temperature, a gas cannot be liquefied no matter how much pressure is applied. The pressure required to liquefy a gas at its critical temperature is called the critical pressure. The critical temperatures and critical pressures of some common substances are given in Table 10.3. Substance.	C: supercritical fluid.
What do you call the movement of a substance from an area of a higher amount toward an area of lower amount? Here are the choices: A. precipitation B. filtration C. diffusion D. extraction	Diffusion is the movement of a substance from an area of a higher amount toward an area of lower amount. A concentration gradient initially exists across the cell membrane. Equilibrium is reached when there is an equal amount of the substance on both sides of the membrane.	C: diffusion.
Each myofibril is made up of two types of proteins, called actin and what? Here are the choices: A. dynein B. elongation C. Fatty Acid D. myosin	Each myofibril is made up of two types of proteins, called actin and myosin. These proteins form thread-like filaments.	D: myosin.
If the experimental value is less than the accepted value, the error is what? Here are the choices: A. caused B. positive C. negative D. effective	If the experimental value is less than the accepted value, the error is negative. If the experimental value is larger than the accepted value, the error is positive. Often, error is reported as the absolute value of the difference in order to avoid the confusion of a negative error. The percent error is the absolute value of the error divided by the accepted value and multiplied by 100%.	C: negative.
According to which process, sublevels and orbitals are filled with electrons in order of increasing energy? Here are the choices: A. hausen B. particle dynamics C. aufbau D. Schrodinger's cat	According to the Aufbau process, sublevels and orbitals are filled with electrons in order of increasing energy. Since the s sublevel consists of just one orbital, the second electron simply pairs up with the first electron as in helium. The next element is lithium and necessitates the use of the next available sublevel, the 2 s .	C: aufbau.
The roughness of interacting surfaces and the magnitude of force pushing one object onto another are two factors related to what force? Here are the choices: A. tension B. energy C. friction D. temperature	The force of friction between these two blocks is related to two factors. The first factor is the roughness of the surfaces that are interacting, which is called the coefficient of friction , (Greek letter mu). The second factor is the magnitude of the force pushing the top block down onto the lower block. It is reasonable that the more forcefully the blocks are pushed together, the more difficult it will be for one to slide over the other. The force pushing these blocks together is the result of gravity acting on the top block and pressing it against the bottom block, which resists the weight with an equal and opposite force called the normal force . The force of friction can be calculated by.	C: friction.
How many types of leptons are there? Here are the choices: A. two B. six C. twelve D. nine	There are also six types of leptons, including electrons. Leptons have an electric charge of either -1 or 0. Electrons, for example, have a charge of -1. Leptons have mass, although the mass of electrons is extremely small.	B: six.
Plants, algae and bacteria are all examples of what type of organism? Here are the choices: A. skeletal B. unicellular C. microbes D. photosynthetic	Photosynthetic organisms include plants, algae, and some bacteria.	D: photosynthetic.
What forms after air cools below its dew point? Here are the choices: A. fog B. plasma C. sleet D. smoke	Advection fog is famous in San Francisco, California. Warm, moist air comes in from the Pacific Ocean. The air blows over the cold California current. When the air cools below its dew point, fog forms. Sea breezes bring the fog onshore.	A: fog.
In hornworts, the horns are the sporophytes that rise up from what? Here are the choices: A. the polyol gametophyte B. the breaza gametophyte C. the roots D. the leaflike gametophyte	Jason Hollinger. In hornworts, the horns are the sporophytes that rise up from the leaflike gametophyte . CC BY 2.0.	D: the leaflike gametophyte.
What generally sets the direction that technology takes? Here are the choices: A. local animals B. random chance C. problems of society D. local weather	The goal of technology is to solve people’s problems. Therefore, the problems of society generally set the direction that technology takes. Technology, in turn, affects society. It may make people’s lives easier or healthier. Two examples are described in Figure below .	C: problems of society.
Living things that feed on others are generally known as what? Here are the choices: A. producers B. consumers C. isolators D. customers		B: consumers.
What is an isotope that is radioactive called? Here are the choices: A. radioisotopes B. radionuclides C. isotopes D. matured isotope	Many elements have one or more isotopes that are radioactive. These isotopes are called radioisotopes. An example of a radioisotope is carbon-14.	A: radioisotopes.
What is a compound that can form ions when it dissolves in water called? Here are the choices: A. sulfate B. compound C. electrolyte D. isolate	acid will form a homogeneous solution with water. (In fact, the solubility of both butanol and pentanoic acid in water is quite low, only about 3 g per 100 g water at 25°C. ) 10. An electrolyte is any compound that can form ions when it dissolves in water. When a strong electrolyte dissolves in water, it dissociates completely to give the constituent ions. In contrast, when a weak electrolyte dissolves in water, it produces relatively few ions in solution.	C: electrolyte.
When using a generator, we are transforming what energy into what energy? Here are the choices: A. mechanical into thermal B. magnetic into kinetic C. thermal into radioactive D. kinetic into electrical	Generators may be set up to produce either direct or alternating current. Generators in cars and most power plants produce alternating current. Regardless of the type of current, all generators change kinetic energy to electrical energy.	D: kinetic into electrical.
What kind of resource is soil? Here are the choices: A. finite B. viable C. nonrenewable D. renewable	Soil is a renewable resource. Sometimes it is lost faster than it can be replaced.	D: renewable.
What is the term for the stalk connecting a leaf to a stem? Here are the choices: A. cuticle B. base C. blades D. petiole	Figure 30.4 Leaves are attached to the plant stem at areas called nodes. An internode is the stem region between two nodes. The petiole is the stalk connecting the leaf to the stem. The leaves just above the nodes arose from axillary buds.	D: petiole.
What are the specialized cells within the brain called? Here are the choices: A. neurons B. electrons C. protons D. ions	Figure 3.9 (a) A typical human brain weighs about 1.5 kg and occupies a volume of roughly 1.1 L. (b) Information is transmitted in brain tissue and throughout the central nervous system by specialized cells called neurons (micrograph shows cells at 1600× magnification). Specialized cells called neurons transmit information between different parts of the central nervous system by way of electrical and chemical signals. Chemical signaling occurs at the interface between different neurons.	A: neurons.
What stimulates the production of milk by the mammary glands following childbirth? Here are the choices: A. estrogen B. prolactin C. melanin D. progesterone	(PRL) in females. Prolactin stimulates the production of milk by the mammary glands following childbirth. Prolactin levels are regulated by the hypothalamic hormones prolactin-releasing hormone (PRH) and prolactin-inhibiting hormone (PIH) which is now known to be dopamine. PRH stimulates the release of prolactin and PIH inhibits it. The posterior pituitary releases the hormone oxytocin, which stimulates contractions during childbirth. The uterine smooth muscles are not very sensitive to oxytocin until late in pregnancy when the number of oxytocin receptors in the uterus peaks. Stretching of tissues in the uterus and vagina stimulates oxytocin release in childbirth. Contractions increase in intensity as blood levels of oxytocin rise until the birth is complete. 22 Hormone production and release are primarily controlled by negative feedback. In negative feedback systems, a stimulus causes the release of a substance whose effects then inhibit further release. In this way, the concentration of hormones in blood is maintained within a narrow range. For example, the anterior pituitary signals the thyroid to release thyroid hormones. Increasing levels of these hormones in the blood then feed back to the hypothalamus and anterior pituitary to inhibit further signaling to the thyroid gland. 24 The main mineralocorticoid is aldosterone, which regulates the concentration of ions in urine, sweat, and saliva. Aldosterone release from the adrenal cortex is stimulated by a decrease in blood concentrations of sodium ions, blood volume, or blood pressure, or an increase in blood potassium levels.	B: prolactin.
In vascular plants, the sporophyte generation is what? Here are the choices: A. resting B. submissive C. dominant D. non-existant	In vascular plants, the sporophyte generation is dominant.	C: dominant.
What organ system transports blood through the body and to and from the lungs? Here are the choices: A. metabolism B. circulatory C. nervous D. digestive	in animals but also in plants. An organ system is a higher level of organization that consists of functionally related organs. Mammals have many organ systems. For instance, the circulatory system transports blood through the body and to and from the lungs; it includes organs such as the heart and blood vessels. Organisms are individual living entities. For example, each tree in a forest is an organism. Single-celled prokaryotes and single-celled eukaryotes are also considered organisms and are typically referred to as microorganisms. All the individuals of a species living within a specific area are collectively called a population. For example, a forest may include many pine trees. All of these pine trees represent the population of pine trees in this forest. Different populations may live in the same specific area. For example, the forest with the pine trees includes populations of flowering plants and also insects and microbial populations. A community is the sum of populations inhabiting a particular area. For instance, all of the trees, flowers, insects, and other populations in a forest form the forest’s community. The forest itself is an ecosystem. An ecosystem consists of all the living things in a particular area together with the abiotic, non-living parts of that environment such as nitrogen in the soil or rain water. At the highest level of organization (Figure 1.16), the biosphere is the collection of all ecosystems, and it represents the zones of life on earth. It includes land, water, and even the atmosphere to a certain extent.	B: circulatory.
"cardio" has become slang for what type of exercise that raises your heart rate for an extended amount of time? Here are the choices: A. cyclical B. aerobic C. anaerobic D. kinetic	"Cardio" has become slang for aerobic exercise that raises your heart rate for an extended amount of time. Cardio can include biking, running, or swimming. Can you guess one of the main organs of the cardiovascular system? Yes, your heart.	B: aerobic.
How many protons do all atoms of a particular element have in their nuclei? Here are the choices: A. zero B. same number C. three D. varying number		B: same number.
One of the five fundamental conservation laws in the universe refers to conservation of what, which is the product of mass and velocity? Here are the choices: A. fluid B. momentum C. energy D. light	The universe has many remarkable qualities, among them a rather beautiful symmetry: the total amount of motion in the universe balances out … always. This law only makes sense if we measure “motion” in a specific way: as the product of mass and velocity. This product, called momentum , can be exchanged from one object to another in a collision. The rapidity with which momentum is exchanged over time is determined by the forces involved in the collision. Conservation of momentum is one of the five fundamental conservation laws in the universe. The other four are conservation of energy, angular momentum, charge conservation and CPT conservation.	B: momentum.
Copper oxide is a result of what two substances mixing? Here are the choices: A. copper and gas B. crystal and oxygen C. metal and oxygen D. copper and oxygen		D: copper and oxygen.
The process of getting oxygen into the body and releasing carbon dioxide is called? Here are the choices: A. persperation B. respiration C. osmosis D. precipitation	The process of getting oxygen into the body and releasing carbon dioxide is called respiration . Sometimes breathing is called respiration, but there is much more to respiration than just breathing. Breathing is only the movement of oxygen into the body and carbon dioxide out of the body. The process of respiration also includes the exchange of oxygen and carbon dioxide between the blood and the cells of the body.	B: respiration.
Someone who believes something despite the evidence is referred to by what term that references a false belief about our planet? Here are the choices: A. conspiracy theorist B. flat-earther C. solid - earther D. geocentric-earther	Flat-earther is a term used to describe someone who believes something despite the evidence. Or who does not believe something despite the evidence. There are actually people who believe that Earth is flat. They say that satellite photos are faked. They believe that the Apollo Moon landings were faked. But there are very few people alive today who actually believe that Earth is flat. There are, however, plenty of people who can be called flat-earthers. These people believe (or disbelieve) something despite the evidence.	B: flat-earther.
Which cells continue the digestion and absorption of nutrients and transport these nutrients to the lymphatic and circulatory systems? Here are the choices: A. myocyte B. blood cells C. neurons D. epithelial cells	Watch this animation (http://openstaxcollege. org/l/sintestine) that depicts the structure of the small intestine, and, in particular, the villi. Epithelial cells continue the digestion and absorption of nutrients and transport these nutrients to the lymphatic and circulatory systems. In the small intestine, the products of food digestion are absorbed by different structures in the villi. Which structure absorbs and transports fats?.	D: epithelial cells.
Pressure is defined as the force per unit area on? Here are the choices: A. surface B. weight C. gravity D. speed	Pressure is defined as the force per unit area on a surface.	A: surface.
What do body cells use for energy? Here are the choices: A. solvents B. sugars C. mixtures D. chlorophyll	A: You may eat a wide variety of carbohydrates—from sugars in fruits to starches in potatoes. However, body cells use only sugars for energy.	B: sugars.
What force pulls people and objects toward the center of the earth? Here are the choices: A. gravity B. magnetism C. variation D. motion	You are already very familiar with Earth’s gravity. It constantly pulls you toward the center of the planet. It prevents you and everything else on Earth from being flung out into space as the planet spins on its axis. It also pulls objects above the surface, from meteors to skydivers, down to the ground. Gravity between Earth and the moon and between Earth and artificial satellites keeps all these objects circling around Earth. Gravity also keeps Earth moving around the sun.	A: gravity.
The rate of decay of carbon-14 does what over time? Here are the choices: A. becomes unstable B. remains stable C. increases D. decreases	The rate of decay of carbon-14 is stable over time.	B: remains stable.
What behavior includes all the ways that animals interact with each other and the environment? Here are the choices: A. adaptation B. interdependence C. animal behavior D. instinct	Did you ever see a dog sit on command? Have you ever watched a cat trying to catch a mouse? These are just two examples of the many behaviors of animals. Animal behavior includes all the ways that animals interact with each other and the environment. Examples of common animal behaviors are pictured in Figure below .	C: animal behavior.
Food chains carry energy from what group to what group? Here are the choices: A. refiners to consumers B. producers to consumers C. decomposers to producers D. consumers to producers	Food chains carry energy from producers (autotrophs) to consumers (heterotrophs). 99% of energy for life comes from the sun via photosynthesis. Note that only nutrients recycle. Energy must continue to flow into the system. Though this food chains "ends" with decomposers, do decomposers, in fact, digest matter from each level of the food chain? (See the Energy Transfer: Decomposers (Advanced) concept).	B: producers to consumers.
What are professionals in technology are generally called ? Here are the choices: A. engineers B. doctors C. scientists D. biomechanics	Companies that design and build roller coasters employ a range of technology professionals. Technology is the application of science to real-world problems. Professionals in technology are generally called engineers . Engineers are creative problem solvers. They use math and science to design and develop just about everything—from roller coasters to video games.	A: engineers.
What force occurs whenever two surfaces come into contact? Here are the choices: A. tension B. vibration C. friction D. gravity	Even if Laura didn’t try to stop the skateboard, it would stop sooner or later. That’s because there’s also friction between the wheels and the pavement. Friction is a force that counters all kinds of motion. It occurs whenever two surfaces come into contact.	C: friction.
The anatomy of primate eyes shows they tend to rely more on vision than what sense, which is dominant in many other mammals? Here are the choices: A. touch B. hearing C. taste D. smell	Primates usually rely more on the sense of vision rather than the sense of smell, which is the dominant sense in many other mammals. The importance of vision in primates is reflected by the bony socket that surrounds and protects the primate eye. Primates have widely spaced eyes in the same plane that give them stereoscopic (3-D) vision, needed for judging distances. Some primates, including humans, have also evolved color vision.	D: smell.
What are sensory cells? Here are the choices: A. specialized neurons or navigable cells B. specialized epithelial or squirm cells C. specialized neurons or epithelial cells D. specialized neurons or squirm cells		C: specialized neurons or epithelial cells.
What is it called when waves interact with other waves? Here are the choices: A. wave collision B. wave impact C. wave interference D. combination interference	Waves interact not only with matter in the ways described above. Waves also interact with other waves. This is called wave interference . Wave interference may occur when two waves that are traveling in opposite directions meet. The two waves pass through each other, and this affects their amplitude. How amplitude is affected depends on the type of interference. Interference can be constructive or destructive.	C: wave interference.
What is the ph level for pure water? Here are the choices: A. ph of 7 B. pH of 0 C. ph of 3.17 D. ph of 6.47	The extremely low hydronium ion concentration of pure water gives pure water a neutral pH of 7. Acids have a pH lower than 7, and bases have a pH higher than 7.	A: ph of 7.
What is vital for nervous system functions that include muscle stimulation, memory formation, and learning? Here are the choices: A. acetylcholine B. glutamate C. glycogen D. thiamine		A: acetylcholine.
The benthic zone is found at the bottom of all of what type of biomes? Here are the choices: A. desert B. well C. aquatic D. space		C: aquatic.
The hydroxyl radical is highly reactive because it has what? Here are the choices: A. paired electron B. unpaired neutron C. unpaired electron D. paired proton	Because the hydroxyl radical has an unpaired electron, it is highly reactive. (This is true of any substance with unpaired electrons, known as a free radical. ) This hydroxyl radical can react with all kinds of biological molecules (DNA, proteins, enzymes, and so on), causing damage to the molecules and disrupting physiological processes. Examples of direct and indirect damage are shown in Figure 21.32.	C: unpaired electron.
Gametes swim with the aid of what structure to the female gametangium, and fertilization ensues? Here are the choices: A. acrosome B. nucleus C. oocyte D. flagella	gametes swim with the aid of their flagella to the female gametangium (the archegonium), and fertilization ensues. The zygote grows into a small sporophyte still attached to the parent gametophyte. It will give rise, by meiosis, to the next generation of spores. Liverwort plants can also reproduce asexually, by the breaking of branches or the spreading of leaf fragments called gemmae. In this latter type of reproduction, the gemmae—small, intact, complete pieces of plant that are produced in a cup on the surface of the thallus (shown in Figure 25.11)—are splashed out of the cup by raindrops. The gemmae then land nearby and develop into gametophytes.	D: flagella.
A phospholipid is a bond between the glycerol component of a lipid and what else? Here are the choices: A. phosphorous molecule B. elemental molecule C. chlorine molecule D. oxygen molecule	Phospholipids As its name suggests, a phospholipid is a bond between the glycerol component of a lipid and a phosphorous molecule. In fact, phospholipids are similar in structure to triglycerides. However, instead of having three fatty acids, a phospholipid is generated from a diglyceride, a glycerol with just two fatty acid chains (Figure 2.23). The third binding site on the glycerol is taken up by the phosphate group, which in turn is attached to a polar “head” region of the molecule. Recall that triglycerides are nonpolar and hydrophobic. This still holds for the fatty acid portion of a phospholipid compound. However, the head of a phospholipid contains charges on the phosphate groups, as well as on the nitrogen atom. These charges make the phospholipid head hydrophilic. Therefore, phospholipids are said to have hydrophobic tails, containing the neutral fatty acids, and hydrophilic heads, containing the charged phosphate groups and nitrogen atom.	A: phosphorous molecule.
What connects the fetus to the placenta? Here are the choices: A. womb B. fallopian tube C. umbilical cord D. amniotic sac	The placenta allows nutrients and wastes to be exchanged between the mother and fetus. The fetus is connected to the placenta through the umbilical cord.	C: umbilical cord.
In desert cactus, thorns that protect the water held in a large, barrel-shaped stem are an example of what? Here are the choices: A. species B. characteristic C. feature D. adaptation	The saguaro cactus pictured in Figure below has adapted in all three ways. When it was still a very small plant, just a few inches high, its shallow roots already reached out as much as 2 meters (7 feet) from the base of the stem. By now, its root system is much more widespread. It allows the cactus to gather as much moisture as possible from rare rainfalls. The saguaro doesn’t have any leaves to lose water by transpiration. It also has a large, barrel-shaped stem that can store a lot of water. Thorns protect the stem from thirsty animals that might try to get at the water inside.	D: adaptation.
What are the most common dietary lipids? Here are the choices: A. triglycerides B. monoglycerides C. phospholipids D. diglycerides	Lipid Digestion A healthy diet limits lipid intake to 35 percent of total calorie intake. The most common dietary lipids are triglycerides, which are made up of a glycerol molecule bound to three fatty acid chains. Small amounts of dietary cholesterol and phospholipids are also consumed. The three lipases responsible for lipid digestion are lingual lipase, gastric lipase, and pancreatic lipase. However, because the pancreas is the only consequential source of lipase, virtually all lipid digestion occurs in the small intestine. Pancreatic lipase breaks down each triglyceride into two free fatty acids and a monoglyceride. The fatty acids include both short-chain (less than 10 to 12 carbons) and long-chain fatty acids.	A: triglycerides.
What process is the opposite of fusion and releases energy only when heavy nuclei are split? Here are the choices: A. osmosis B. fission C. activation D. diffusion	Fission is the opposite of fusion and releases energy only when heavy nuclei are split. As noted in Fusion, energy is released if the products of a nuclear reaction have a greater binding energy per nucleon ( BE / A ) than the parent nuclei. Figure 32.25.	B: fission.
Visible light is the narrow segment of what, to which the normal human eye responds? Here are the choices: A. molecular spectrum B. radio spectrum C. electromagnetic spectrum D. phenomena spectrum	Visible Light Visible light is the narrow segment of the electromagnetic spectrum to which the normal human eye responds. Visible light is produced by vibrations and rotations of atoms and molecules, as well as by electronic transitions within atoms and molecules. The receivers or detectors of light largely utilize electronic transitions. We say the atoms and molecules are excited when they absorb and relax when they emit through electronic transitions. Figure 24.16 shows this part of the spectrum, together with the colors associated with particular pure wavelengths. We usually refer to visible light as having wavelengths of between 400 nm and 750 nm. (The retina of the eye actually responds to the lowest ultraviolet frequencies, but these do not normally reach the retina because they are absorbed by the cornea and lens of the eye. ) Red light has the lowest frequencies and longest wavelengths, while violet has the highest frequencies and shortest wavelengths. Blackbody radiation from the Sun peaks in the visible part of the spectrum but is more intense in the red than in the violet, making the Sun yellowish in appearance.	C: electromagnetic spectrum.
Bromine is much less abundant than fluorine or chlorine, but it is easily recovered from seawater, which contains about 65 mg of br− per what? Here are the choices: A. liter B. pound C. foot D. gallon	electrolysis2NaOH ( aq ) + Cl2 ( g ) + H 2 ( g ) Bromine is much less abundant than fluorine or chlorine, but it is easily recovered from seawater, which contains about 65 mg of Br− per liter. Salt lakes and underground brines are even richer sources; for example, the Dead Sea contains 4 g of Br− per liter. Iodine is the least abundant of the nonradioactive halogens, and it is a relatively rare element. Because of its low electronegativity, iodine tends to occur in nature in an oxidized form. Hence most commercially important deposits of iodine, such as those in the Chilean desert, are iodate salts such as Ca(IO3)2. The production of iodine from such deposits therefore requires reduction rather than oxidation. The process is typically carried out in two steps: reduction of iodate to iodide with sodium hydrogen sulfite, followed by reaction of iodide with additional iodate: Equation 22.41.	A: liter.
Karyotyping shows whether what structures, which contain genetic information, are normal in number and appearance? Here are the choices: A. neutrons B. nucleoids C. ribosomes D. chromosomes		D: chromosomes.
Real gases deviate from ideal form at high pressure and what other thermodynamic condition? Here are the choices: A. low pressure B. high temperatures C. low temperatures D. high winds	Real gases deviate from ideal gases at high pressures and at low temperatures.	C: low temperatures.
Organic substances, including proteins, carbohydrates, and oils, contain what element? Here are the choices: A. acid B. carbon C. iron D. oxygen	A mineral is an inorganic substance. It was not made by living organisms. Organic substances contain carbon. Some types of organic substances are proteins, carbohydrates, and oils. Everything else is inorganic. In a few cases, living organisms make inorganic materials. The calcium carbonate shells made by marine animals are inorganic.	B: carbon.
What term describes anything that occupies space and has mass, and is generally divided into three states? Here are the choices: A. matter B. galaxy C. stuff D. lquid	Matter is anything that occupies space and has mass. The three states of matter are solid, liquid, and gas. A physical change involves the conversion of a substance from one state of matter to another, without changing its chemical composition. Most matter consists of mixtures of pure substances, which can behomogeneous (uniform in composition) or heterogeneous (different regions possess different compositions and properties). Pure substances can be either chemical compounds or elements. Compounds can be broken down into elements by chemical reactions, but elements cannot be separated into simpler substances by chemical means. The properties of substances can be classified as either physical or chemical. Scientists can observe physical properties without changing the composition of the substance, whereas chemical propertiesdescribe the tendency of a substance to undergo chemical changes (chemical reactions) that change its chemical composition. Physical properties can be intensive or extensive. Intensive properties are the same for all samples; do not depend on sample size; and include, for example, color, physical state, and melting and boiling points. Extensive properties depend on the amount of material and include mass and volume. The ratio of two extensive properties, mass and volume, is an important intensive property called density.	A: matter.
When light strikes the rods and cones, they hyperpolarize, shutting off their release of what? Here are the choices: A. vitreous fluid B. enzyme C. glutamate D. dopamine		C: glutamate.
The heart contracts rhythmically to pump what to the lungs and the rest of the body? Here are the choices: A. Bile B. Cerumen C. blood D. Chyle	The heart contracts rhythmically to pump blood to the lungs and the rest of the body. Specialized cardiac muscle cells trigger the contractions.	C: blood.
What do light emitters do to what you see? Here are the choices: A. subtract frequencies B. divide frequencies C. add frequencies D. block frequencies	Discussions of colors can sometimes become confusing because of the difference between light emitters and light absorbers. Light absorbers, such as dyes and pigments, absorb frequencies from those that you see, while light emitters add frequencies to what you see. If I were to shine red light, green light, and blue light into your eye all at the same time, you would likely see some variation of white. If I were to mix red paint, green paint, and blue paint together, you would likely see black or some very dark color.	C: add frequencies.
A turbine using tides in the ocean can create what type of energy? Here are the choices: A. diffused B. electricity C. conversion D. kinetic	Tides in the ocean can also turn a turbine to create electricity. This energy can then be stored until needed ( Figure below ).	B: electricity.
The atomic number is the same as the number of what in an atom? Here are the choices: A. electrons B. ions C. protons D. neutrons	The number of protons in an atom is called its atomic number. This is also unique for each element.	C: protons.
What is the closed circulatory system of humans and other vertebrates called? Here are the choices: A. cardiovascular system B. respiratory system C. digestive system D. reproductive system		A: cardiovascular system.
"red-shift" refers to a shift toward red in the spectrum from what celestial bodies? Here are the choices: A. galaxies B. stars C. comets D. planets	The spectrum from stars is shifted toward the red; this is known as red-shift. Red-shift of galaxies is evidence that the Universe is expanding.	B: stars.
What is the name for substances with a ph above 7? Here are the choices: A. protein B. bases C. nutrient D. acid	Bases have a lower concentration of hydronium ions than pure water, and a pH higher than 7.	B: bases.
The subducting oceanic plate does what as it reenters the mantle? Here are the choices: A. melts B. evaporates C. disappers D. freezes	As you would expect, where plates collide there are lots of intense earthquakes and volcanic eruptions. The subducting oceanic plate melts as it reenters the mantle. The magma rises and erupts. This creates a volcanic mountain range near the coast of the continent. This range is called a continental arc . The Andes Mountains, along the western edge of South America, are a volcanic arc ( Figure below ).	A: melts.
Which stage of development is a period during which apoptosis is widespread and plays a crucial role? Here are the choices: A. infancy B. puberty C. embryonic D. transgenic		C: embryonic.
What orifice in the body is particularly helpful in both digestion and respiration? Here are the choices: A. anus B. nostril C. nose D. mouth		D: mouth.
What subphylum, which includes crabs and crayfish, represents the dominant aquatic arthropods? Here are the choices: A. sponges B. crustaceans C. invertebrates D. arachnids	Crustaceans, such as shrimp, lobsters, crabs, and crayfish, are the dominant aquatic arthropods. A few crustaceans are [3] terrestrial species like the pill bugs or sow bugs. The number of described crustacean species stands at about 47,000. Although the basic body plan in crustaceans is similar to the Hexapoda—head, thorax, and abdomen—the head and thorax may be fused in some species to form a cephalothorax, which is covered by a plate called the carapace (Figure 15.22). The exoskeleton of many species is also infused with calcium carbonate, which makes it even stronger than in other arthropods. Crustaceans have an open circulatory system in which blood is pumped into the hemocoel by the dorsal heart. Most crustaceans typically have separate sexes, but some, like barnacles, may be hermaphroditic. Serial hermaphroditism, in which the gonad can switch from producing sperm to ova, is also found in some crustacean species. Larval stages are seen in the early development of many crustaceans. Most crustaceans are carnivorous, but detritivores and filter feeders are also common.	B: crustaceans.
What do neurons pass to the next neuron? Here are the choices: A. contaminants B. receptors C. blood D. neurotransmitters	Did you ever watch a relay race? After the first runner races, he or she passes the baton to the next runner, who takes over. Neurons are a little like relay runners. Instead of a baton, they pass neurotransmitters to the next neuron. Examples of neurotransmitters are chemicals such as serotonin, dopamine, and adrenaline.	D: neurotransmitters.
What determines which type of precipitation falls in the atmosphere? Here are the choices: A. air density B. air temperature C. moon phase D. time of day	Why does it snow instead of rain? Air temperature determines which type of precipitation falls. Rain falls if the air temperature is above freezing (0° C or 32° F). Frozen precipitation falls if the air or ground is below freezing. Frozen precipitation may fall as snow , sleet , or freezing rain . Below, you can see how the different types form ( Figure below ).	B: air temperature.
The main functions of what complex carbohydrates are to store energy and form structural tissues? Here are the choices: A. polysaccharides B. polypeptides C. oligosaccharides D. monosaccharides	The main functions of polysaccharides are to store energy and form structural tissues. Examples of several other polysaccharides and their roles are listed in the Table below . These complex carbohydrates play important roles in living organisms.	A: polysaccharides.
High consumption of saturated fats is linked to an increased risk of what disease? Here are the choices: A. cardiovascular disease B. pulmonary edema C. diabetes D. high blood pressure	Unsaturated fat is generally considered to be healthier because it contains fewer calories than an equivalent amount of saturated fat. Additionally, high consumption of saturated fats is linked to an increased risk of cardiovascular disease. Some examples of foods with high concentrations of saturated fats include butter, cheese, lard, and some fatty meats. Foods with higher concentrations of unsaturated fats include nuts, avocado, and vegetable oils such as canola oil and olive oil. The Figure below shows the percentages of fat types in some common foods.	A: cardiovascular disease.
What does hair get its color from? Here are the choices: A. fluorescent pigments B. stimulating pigments C. melanin pigments D. elasticity pigments	5.2 Accessory Structures of the Skin Accessory structures of the skin include hair, nails, sweat glands, and sebaceous glands. Hair is made of dead keratinized cells, and gets its color from melanin pigments. Nails, also made of dead keratinized cells, protect the extremities of our.	C: melanin pigments.
What type of animal in the sea spend most of their lives as medusae? Here are the choices: A. fish B. sharks C. jellyfish D. whales	Jellyfish spend most of their lives as medusae. They live virtually everywhere in the ocean. They prey on zooplankton, other invertebrates, and the eggs and larvae of fish.	C: jellyfish.
Desert plants have evolved processes to conserve water and deal with harsh conditions. a more efficient use of co2 allows plants to adapt to living with what? Here are the choices: A. less competition B. less water C. more water D. more sunlight	perpendicular to the surface at the point where the ray strikes the surface.	B: less water.
Plants, cyanobacteria, and algae are living things that undergo what process and produce glucose? Here are the choices: A. photosynthesis B. cytoplasmic transfer C. cellular respiration D. glycolysis	Living things that undergo photosynthesis and produce glucose include plants, cyanobacteria, and algae.	A: photosynthesis.
All chemical changes involve a transfer of what? Here are the choices: A. fuel B. heating C. energy D. Water	All chemical changes involve a transfer of energy. When zinc reacts with hydrochloric acid, the test tube becomes very warm as energy is released during the reaction. Some other reactions absorb energy. While energy changes are a potential sign of a chemical reaction, care must be taken to ensure that a chemical reaction is indeed taking place. Physical changes may also involve a transfer of energy. A solid absorbs energy when it melts, and the condensation of a gas releases energy. The only way to be certain that a chemical reaction has occurred is to test the composition of the substances after the change has taken place to see if they are different from the starting substances.	C: energy.
What is the unique larval form of mollusks called? Here are the choices: A. hydra B. microfilariae C. scallop D. trochophore	Mollusks reproduce sexually. Most species have separate male and female sexes. Gametes are released into the mantle cavity. Fertilization may be internal or external, depending on the species. Fertilized eggs develop into larvae. There may be one or more larval stages. Each one is different from the adult stage. Mollusks have a unique larval form called a trochophore . It is a tiny organism with cilia for swimming.	D: trochophore.
A voltage source and a conductor are common to all what? Here are the choices: A. thermometers B. cooling circuits C. electric circuits D. magnets	All electric circuits have at least two parts: a voltage source and a conductor. They may have other parts as well, such as light bulbs and switches, as in the simple circuit seen in the Figure below . To see an animation of a circuit like this one, go to: http://www. rkm. com. au/animations/animation-electrical-circuit. html.	C: electric circuits.
Root systems are mainly of two types. dicots have a tap root system, while monocots have a what? Here are the choices: A. fibrous root system B. attaching root system C. runner root system D. long root system	Types of Root Systems Root systems are mainly of two types (Figure 30.15). Dicots have a tap root system, while monocots have a fibrous root system. A tap root system has a main root that grows down vertically, and from which many smaller lateral roots arise. Dandelions are a good example; their tap roots usually break off when trying to pull these weeds, and they can regrow another shoot from the remaining root). A tap root system penetrates deep into the soil. In contrast, a fibrous root system is located closer to the soil surface, and forms a dense network of roots that also helps prevent soil erosion (lawn grasses are a good example, as are wheat, rice, and corn). Some plants have a combination of tap roots and fibrous roots. Plants that grow in dry areas often have deep root systems, whereas plants growing in areas with abundant water are likely to have shallower root systems.	A: fibrous root system.
Enzymes in cellular reactions work to do what to the reaction? Here are the choices: A. speed it up B. slow it down C. increase yield D. decrease heat	Enzymes are extremely efficient in speeding up reactions. They can catalyze up to several million reactions per second. As a result, the difference in rates of biochemical reactions with and without enzymes may be enormous. A typical biochemical reaction might take hours or even days to occur under normal cellular conditions without an enzyme, but less than a second with an enzyme.	A: speed it up.
Bony fish can live in either of what type of aquatic biome? Here are the choices: A. saltwater or freshwater B. estuaries or saltwater C. oceans or estuaries D. coral reefs or freshwater	Bony fish may live in salt water or freshwater. They consume a wide range of foods. For example, they may eat algae, smaller fish, detritus, or dead organisms, depending on the species of fish.	A: saltwater or freshwater.
What is categorized by the forces holding the individual atoms, ions, or molecules together? Here are the choices: A. solids B. oils C. liquids D. gases	Solids can be categorized by the forces holding the individual atoms, ions, or molecules together. The Table below summarizes the properties of different solids:.	A: solids.
What are the two main types of air pollutants? Here are the choices: A. a and b B. primary and secondary C. good and bad D. new and old	There are two main types of air pollutants: primary and secondary. Most air pollutants come from burning fossil fuels. Some come from burning forests. Some are due to the evaporation of chemicals.	B: primary and secondary.
The job of the nucleolus is to build what? Here are the choices: A. ribosomes B. cells C. electrons D. chromosomes	The nucleus of many cells also contains a central region called the nucleolus . The job of the nucleolus is to build ribosomes. These ribosomes flow out the nuclear pores into the cytoplasm. Ribosomes are organelles that make proteins in the cytoplasm. See the composition of the nucleus pictured below ( Figure below ).	A: ribosomes.
For many decades, scientists have known that atoms consist of electrons and other particles called protons and? Here are the choices: A. nanoparticles B. rods C. neutrons D. waves	For many decades, scientists have known that atoms consist of electrons and other particles called protons and neutrons. Recently they found that there are even smaller particles in atoms. Scientists call these extremely tiny particles by the funny name of quarks. As you can see in this diagram, there are several different kinds of quarks, called up quarks, down quarks, top quarks, bottom quarks, charm quarks, and strange quarks. In this chapter you’ll learn about these unusual particles and also other particles inside the atom.	C: neutrons.
Patients with familial hypercholesterolemia have life-threatening levels of cholesterol because their cells cannot clear what particles from their blood? Here are the choices: A. high - density lipoprotein (hdl) B. iron (Fe) C. oxygen (O) D. low-density lipoprotein (ldl)	In receptor-mediated endocytosis, as in phagocytosis, clathrin is attached to the cytoplasmic side of the plasma membrane. If uptake of a compound is dependent on receptor-mediated endocytosis and the process is ineffective, the material will not be removed from the tissue fluids or blood. Instead, it will stay in those fluids and increase in concentration. Some human diseases are caused by the failure of receptor-mediated endocytosis. For example, the form of cholesterol termed low-density lipoprotein or LDL (also referred to as “bad” cholesterol) is removed from the blood by receptor-mediated endocytosis. In the human genetic disease familial hypercholesterolemia, the LDL receptors are defective or missing entirely. People with this condition have life-threatening levels of cholesterol in their blood, because their cells cannot clear LDL particles from their blood. Although receptor-mediated endocytosis is designed to bring specific substances that are normally found in the extracellular fluid into the cell, other substances may gain entry into the cell at the same site. Flu viruses, diphtheria, and cholera toxin all have sites that cross-react with normal receptor-binding sites and gain entry into cells.	D: low-density lipoprotein (ldl).
What action, performed multiple times daily, is the single biggest use of water in the home? Here are the choices: A. taking showers B. flushing the toilet C. watering plants D. washing clothes	It’s easy to save water at home. If you save even a few gallons a day you can make a big difference over the long run. The best place to start saving water is in the bathroom. Toilet flushing is the single biggest use of water in the home. Showers and baths are the next biggest use. Follow the tips below to save water at home.	B: flushing the toilet.
What is a form of mechanical energy that starts with a vibration in matter? Here are the choices: A. solar energy B. industrial energy C. sound energy D. electrical energy	6. Sound energy is a form of mechanical energy that starts with a vibration in matter. For example, the singer’s voice starts with vibrations of his vocal cords, which are folds of tissue in his throat. The vibrations pass to surrounding particles of matter and then from one particle to another in waves. Sound waves can travel through air, water, and other substances, but not through empty space.	C: sound energy.
What's caused by damaged capillaries in the kidneys so the nephrons can no longer filter blood? Here are the choices: A. colon failure B. kidney failure C. bacteria failure D. sponge failure	Untreated diabetes may damage capillaries in the kidneys so the nephrons can no longer filter blood. This is called kidney failure. The only cure for kidney failure is to receive a healthy transplanted kidney from a donor. Until that happens, a patient with kidney failure can be kept alive by artificially filtering the blood through a machine. This is called hemodialysis. You can see how it works in Figure below .	B: kidney failure.
What do roots bring in from the soil into the plant? Here are the choices: A. pesticides and chlorophyll B. water and nutrients C. dirt and minerals D. hormones and fertilizer		B: water and nutrients.
In addition to spiral cleavage, protostomes also undergo which other form of cleavage? Here are the choices: A. dispersive B. diagonal C. determinate D. straight	There is a second distinction between the types of cleavage in protostomes and deuterostomes. In addition to spiral cleavage, protostomes also undergo determinate cleavage. This means that even at this early stage, the developmental fate of each embryonic cell is already determined. A cell does not have the ability to develop into any cell type. In contrast, deuterostomes undergo indeterminate cleavage, in which cells are not yet pre-determined at this early stage to develop into specific cell types. These cells are referred to as undifferentiated cells. This characteristic of deuterostomes is reflected in the existence of familiar embryonic stem cells, which have the ability to develop into any cell type until their fate is programmed at a later developmental stage.	C: determinate.
What term is used to describe animals with three germ layers? Here are the choices: A. triplegerm B. triploblasts C. multilayer D. sporozoans	Watch this video (http://openstaxcollege. org/l/symmetry2) to see a quick sketch of the different types of body symmetry. Layers of Tissues Most animal species undergo a layering of early tissues during embryonic development. These layers are called germ layers. Each layer develops into a specific set of tissues and organs. Animals develop either two or three embryonic germs layers (Figure 15.5). The animals that display radial symmetry develop two germ layers, an inner layer (endoderm) and an outer layer (ectoderm). These animals are called diploblasts. Animals with bilateral symmetry develop three germ layers: an inner layer (endoderm), an outer layer (ectoderm), and a middle layer (mesoderm). Animals with three germ layers are called triploblasts.	B: triploblasts.
Due to similar function, the wings of bats and birds are referred to as what type of structures? Here are the choices: A. matching structures B. analogous structures C. Identical structures D. symmetrical structures	John Romanes, modified by CK-12 Foundation. Wings of bats and birds are analogous structures . Public Domain.	B: analogous structures.
If the amount of force of that is applied is increased, what happens to the work that a machine is producing? Here are the choices: A. it is easier B. it's unchanged C. it is harder D. it's variable	Machines make work easier by increasing the amount of force that is applied, increasing the distance over which the force is applied, or changing the direction in which the force is applied. Contrary to popular belief, machines do not increase the amount of work that is done. They just change how the work is done. So if a machine increases the force applied, it must apply the force over a shorter distance. Similarly, if a machine increases the distance over which the force is applied, it must apply less force.	A: it is easier.
What is the name for speed with a direction? Here are the choices: A. velocity B. acceleration C. distance D. trajectory	Speed represents how quickly an object is moving through space. Velocity is speed with a direction, making it a vector quantity. If an object’s velocity changes with time, the object is said to be accelerating. As we’ll see in the next chapters, understanding the acceleration of an object is the key to understanding its motion. We will assume constant acceleration throughout this chapter.	A: velocity.
How many types of mechanical waves are there? Here are the choices: A. nine B. one C. five D. three	There are three types of mechanical waves. They differ in how they travel through a medium. The three types are transverse, longitudinal, and surface waves. All three types are described in detail below.	D: three.
What is required for a decay chain to end? Here are the choices: A. unstable end-product B. stable end-product C. radioactive cascade D. stable half-life	We have talked about the activity and decay of individual isotopes. In the real world, there is a decay chain that takes place until a stable end-product is produced. For U-238, the chain is a long one, with a mix of isotopes having very different half-lives. The end of the chain resides in lead, a stable element that does not decay further.	B: stable end-product.

Subsets and Splits

No community queries yet

The top public SQL queries from the community will appear here once available.