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What type of young do scorpions produce? Here are the choices: A. twins B. guppies C. identical D. live	Unlike the majority of arachnids, scorpions produce live young. The young are carried about on the mother’s back until they have molted at least once. They reach an age of between four to 25 years.	D: live.
The chloroplast integrates the two stages of what process? Here are the choices: A. defacation B. photosynthesis C. breathing D. polarization		B: photosynthesis.
What is the name for the amount of water vapor in the air? Here are the choices: A. humidity B. ambient C. heat D. viscosity	Humidity is the amount of water vapor in the air. Humidity varies from place to place. It also varies in the same place from season to season. On a summer day in Atlanta, Georgia, humidity is high. The air feels very heavy and sticky. On a winter day in Flagstaff, Arizona, humidity is low. The air sucks moisture out of your nose and lips. Humidity can change rapidly if a storm comes in. Humidity can vary over a short distance, like near a lake. Even when humidity is at its highest, water vapor makes up only about 4% of the atmosphere.	A: humidity.
What is the body system that digests food mechanically and chemically and absorbs nutrients? Here are the choices: A. metabolism system B. digestive system C. internal system D. ingestion system	The digestive system is the body system that digests food mechanically and chemically and absorbs nutrients. The digestive system also eliminates solid food waste. The major organs of the digestive system include the mouth, esophagus, stomach, and small and large intestines. These organs make up the long tube called the gastrointestinal (GI) tract, which goes from the mouth to the anus.	B: digestive system.
What is measured with a personal dosimeter? Here are the choices: A. internal temperature B. exposure to radioactivity C. alcohol concentration D. blood insulin	Measurement of exposure to radioactivity is important for anyone who deals with radioactive materials on a regular basis. Perhaps the simplest device is a personal dosimeter, which is a film badge that will fog up when exposed to radiation. The amount of fogging is proportional to the amount of radiation present.	B: exposure to radioactivity.
Which plants sometimes colonize areas by disrupting interactions between native organisms? Here are the choices: A. denser exotic plants B. bacteria exotic plants C. carnivorous exotic plants D. invasive exotic plants		D: invasive exotic plants.
What are electromagnetic waves with the longest wavelengths called? Here are the choices: A. channel waves B. radio waves C. sound waves D. infrared waves	Electromagnetic waves on the left side of the Figure above are called radio waves. Radio waves are electromagnetic waves with the longest wavelengths. They may have wavelengths longer than a soccer field. They are also the electromagnetic waves with the lowest frequencies. With their low frequencies, they have the least energy of all electromagnetic waves. Nonetheless, radio waves are very useful. They are used for radio and television broadcasts and many other purposes. You can learn more about radio waves, including how they were discovered, at this URL: http://www. youtube. com/watch?v=al7sFP4C2TY .	B: radio waves.
Resonance has been used in what kind of human-made recreational objects since prehistoric times? Here are the choices: A. arrows B. paintbrushes C. musical instruments D. toys	Figure 17.33 Resonance has been used in musical instruments since prehistoric times. This marimba uses gourds as resonance chambers to amplify its sound. (credit: APC Events, Flickr).	C: musical instruments.
What is the strength of an earthquake called? Here are the choices: A. waves B. magnitude C. power D. force	Earthquake: What Does Magnitude Mean? at http://www. livescience. com/20538-earthquake-magnitude-video. html (2:00).	B: magnitude.
What organs need constant pressure to filter the blood? Here are the choices: A. lungs B. kidneys C. dialysis D. arteries	The kidneys also need constant pressure to filter the blood. When the blood pressure drops too low, the kidneys increase the pressure. One way is by producing angiotensin, a blood vessel-constricting protein. This protein also signals the body to retain sodium and water. Together, the constriction of blood vessels and retention of sodium and water help restore normal blood pressure.	B: kidneys.
After an infection has been brought under control and most cytotoxic t cells die off, a few remain as what? Here are the choices: A. natural killer cells B. memory cells C. control cells D. b cells	After an infection has been brought under control, most cytotoxic T cells die off. However, a few remain as memory cells. If the same pathogen enters the body again, the memory cells mount a rapid immune response. They quickly produce many copies of cytotoxic T cells specific to the antigen of that pathogen.	B: memory cells.
How do lancelets reproduce? Here are the choices: A. sexually B. asexually C. parthenogenesis D. aerobically	There are only about 25 living species of lancelets. They inhabit the ocean floor where the water is shallow. Lancelet larvae are free-swimming. The adults can swim but spend most of their time buried in the sand. Like tunicates, lancelets are filter feeders. They take in water through their mouth and expel it through an opening called the atriopore (see Figure below ). Lancelets reproduce sexually and have separate sexes.	A: sexually.
What is the storage form of glucose in humans and other vertebrates? Here are the choices: A. glycogen B. fructose C. placenta D. neurons	Glycogen is the storage form of glucose in humans and other vertebrates and is made up of monomers of glucose. Glycogen is the animal equivalent of starch and is a highly branched molecule usually stored in liver and muscle cells. Whenever blood glucose levels decrease, glycogen is broken down to release glucose in a process known as glycogenolysis. Cellulose is the most abundant natural biopolymer. The cell wall of plants is mostly made of cellulose; this provides structural support to the cell. Wood and paper are mostly cellulosic in nature. Cellulose is made up of glucose monomers that are linked by β 1-4 glycosidic bonds (Figure 3.10).	A: glycogen.
What two factors influence the pressure of fluids? Here are the choices: A. time and temperature B. depth and gravity C. temperature and density D. depth and density	Two factors influence the pressure of fluids. They are the depth of the fluid and its density.	D: depth and density.
Although it is the easiest to observe, what property is not ideal as a sole way to identify minerals? Here are the choices: A. temperature B. density C. color D. composition	Color is probably the easiest property to observe. Unfortunately, you can rarely identify a mineral only by its color. Sometimes, different minerals are the same color. For example, you might find a mineral that is a golden color and think it is gold. But it might actually be pyrite, or “fool's gold,” which is made of iron and sulfide. It contains no gold atoms.	C: color.
Where are bile acids, needed to emulsify lipids, stored in the body? Here are the choices: A. cerebellum B. gallbladder C. liver D. womb	Triglycerides in the diet are digested in the small intestine. Since lipids are not water-soluble, they are emulsified with the help of bile acids, which are produced by the liver and stored in the gall bladder. Bile acids are cholesterol-derived steroids that also contain a water-soluble component. The nonpolar region of these acids can interact with triglycerides, and the water-soluble portion allows the entire complex to dissolve in the aqueous environment within the body.	B: gallbladder.
What type of molecule is first broken down in cellular respiration? Here are the choices: A. oxygen molecule B. glucose molecule C. hydrogen molecule D. fructose molecule	Cellular respiration takes place in the stages shown here. The process begins with a molecule of glucose, which has six carbon atoms. What happens to each of these atoms of carbon?.	B: glucose molecule.
The rate at which the body uses food energy to sustain life and to do different activities is called the what? Here are the choices: A. metabolic rate B. calorie rate C. hormonal rate D. life cycle	Power Consumed at Rest The rate at which the body uses food energy to sustain life and to do different activities is called the metabolic rate. The total energy conversion rate of a person at rest is called the basal metabolic rate (BMR) and is divided among various systems in the body, as shown in Table 7.4. The largest fraction goes to the liver and spleen, with the brain coming next. Of course, during vigorous exercise, the energy consumption of the skeletal muscles and heart increase markedly. About 75% of the calories burned in a day go into these basic functions. The BMR is a function of age, gender, total body weight, and amount of muscle mass (which burns more calories than body fat). Athletes have a greater BMR due to this last factor.	A: metabolic rate.
How many valence electrons does carbon have? Here are the choices: A. four B. five C. two D. one	Carbon has four valence electrons, so it can achieve a full outer energy level by forming four covalent bonds. When it bonds only with hydrogen, it forms compounds called hydrocarbons.	A: four.
What word describes a molecule that repels polar water? Here are the choices: A. hydrophobic B. monophobic C. soluble D. hydrophonic	The other end of each phospholipid molecule is nonpolar and has no electric charge. This end of the phospholipid molecule repels polar water and is described as hydrophobic, or “water hating. ”.	A: hydrophobic.
Which pollution can cause lung cancer and can also make asthma and other diseases worse? Here are the choices: A. climate pollution B. air pollution C. air pollination D. water pollution	Besides pathogens, many other dangers in the environment may negatively affect human health. For example, air pollution can cause lung cancer. It can also make asthma and other diseases worse. Bioterrorism is another potential threat in the environment. It may poison large numbers of people or cause epidemics of deadly diseases. But the worst thing you can do to yourself is smoke cigarettes.	B: air pollution.
Counterweights and diagonal steel beams are used in buildings to hold down what? Here are the choices: A. sway B. inertia C. gravity D. traction	Larger buildings must sway, but not so much that they touch nearby buildings. Counterweights and diagonal steel beams are used to hold down sway.	A: sway.
The major component of what cellular structures is the phospholipid bilayer? Here are the choices: A. nuclei B. cytoplasm C. ribosomes D. cell membranes	Figure 3.20 The phospholipid bilayer is the major component of all cellular membranes. The hydrophilic head groups of the phospholipids face the aqueous solution. The hydrophobic tails are sequestered in the middle of the bilayer.	D: cell membranes.
The cytoskeleton crisscrosses the cytoplasm, this gives what to the cell? Here are the choices: A. internal framework B. internal passageway C. external passageway D. external framework	The cytoplasm consists of everything inside the plasma membrane, including watery cytosol and organelles. The cytoplasm suspends the organelles and does other jobs. The cytoskeleton crisscrosses the cytoplasm and gives the cell an internal framework.	A: internal framework.
Initiation, elongation, and termination are the three steps of what? Here are the choices: A. transcription B. mutation C. respiration D. differentiation	Transcription takes place in three steps: initiation, elongation, and termination. The steps are illustrated in Figure below .	A: transcription.
What do we call the most widely accepted cosmological explanation of how the universe formed? Here are the choices: A. big light theory B. big crunch theory C. big bang theory D. singularity theory	There is a great deal of evidence that the Universe started with a big bang. The Big Bang theory is the most widely accepted cosmological explanation of how the Universe formed. Think about the expanding Universe, then reverse it. If we start at the present and go back into the past, the Universe gets smaller. What is the end result of a contracting Universe? A point.	C: big bang theory.
Angiosperms possess reproductive structures that attract animals that perform what role? Here are the choices: A. evolution B. isolation C. vegetation D. pollination	structure in angiosperms consisting of male and female reproductive structures that attracts animal pollinators.	D: pollination.
What kind of tissue consists of trabeculae and forms the inner layer of all bones? Here are the choices: A. denser bone tissue B. corregated bone tissue C. spongy bone tissue D. flotsam bone tissue	Chapter 38 1 Figure 38.19B 3 Figure 38.38 In the presence of Sarin, acetycholine is not removed from the synapse, resulting in continuous stimulation of the muscle plasma membrane. At first, muscle activity is intense and uncontrolled, but the ion gradients dissipate, so electrical signals in the T-tubules are no longer possible. The result is paralysis, leading to death by asphyxiation. 4 A 6 D 8 B 10 A 12 B 14 C 16 D 18 D 20 The female pelvis is tilted forward and is wider, lighter, and shallower than the male pelvis. It is also has a pubic angle that is broader than the male pelvis. 22 Compact bone tissue forms the hard external layer of all bones and consists of osteons. Compact bone tissue is prominent in areas of bone at which stresses are applied in only a few directions. Spongy bone tissue forms the inner layer of all bones and consists of trabeculae. Spongy bone is prominent in areas of bones that are not heavily stressed or at which stresses arrive from many directions. 24 The hip joint is flexed and the knees are extended. 26 Because ATP is required for myosin to release from actin, muscles would remain rigidly contracted until more ATP was available for the myosin cross-bridge release. This is why dead vertebrates undergo rigor mortis. 28 Neurons will not be able to release neurotransmitter without calcium. Skeletal muscles have calcium stored and don’t need any from the outside.	C: spongy bone tissue.
What is the most important factor in determining the type of soil that forms in a particular area? Here are the choices: A. climate B. migration C. landscape D. altitude	Climate is the most important factor in determining the type of soil that forms in a particular area.	A: climate.
Energy constantly changes back and forth between kinetic and what type of energy? Here are the choices: A. potential B. physical C. practical D. mechanical	Energy also constantly changes back and forth between kinetic and potential energy. Kinetic energy is the energy of movement. For example, a ball falling through the air has kinetic energy because it is moving ( Figure below ). The random motion of molecules is due to kinetic energy, and the driving force behind diffusion.	A: potential.
The tendency of an object to resist a change in its motion is called what? Here are the choices: A. stabilization B. kenetic force C. inertia D. isolation	Inertia is the tendency of an object to resist a change in its motion. All objects have inertia, whether they are stationary or moving. Inertia explains Newton’s first law of motion, which states that an object at rest will remain at rest and an object in motion will stay in motion unless it is acted on by an unbalanced force. That’s why Newton’s first law of motion is sometimes called the law of inertia. You can see an animation of inertia at this URL:.	C: inertia.
When land used for mining or other purposes is restored to its natural state, what do you call the process, which is often mandated by law? Here are the choices: A. irrigation B. urban renewal C. reclamation D. removal	U. S. law states that once mining is complete, the land must be restored to its natural state. This process is called reclamation . A pit may be refilled with dirt. It may be filled with water to create a lake. The pits may be turned into landfills. Underground mines may be sealed off or left open as homes for bats. The land is reshaped. Native plants are planted.	C: reclamation.
There are how many visual clues to indicate a chemical reaction? Here are the choices: A. five B. four C. three D. seven	chemical reaction: Involves a transfer of energy. There are four visual clues to indicate a chemical reaction.	B: four.
Genetic traits are characteristics encoded in what? Here are the choices: A. dna B. bacteria C. rna D. nuclei	Characteristics that are encoded in DNA are called genetic traits . Different types of human traits are inherited in different ways. Some human traits have simple inheritance patterns like the traits that Gregor Mendel studied in pea plants. Other human traits have more complex inheritance patterns.	A: dna.
In 1802, charles and gay-lussac both proposed that for a fixed amount of gas at a constant pressure, what is directly proportional to its absolute temperature? Here are the choices: A. volume B. density C. air D. liquid	Various studies were done on the effects of temperature changes on both pressure and volume by two prominent French scientists, Jacques Charles (1746-1823) and Joseph Louis Gay-Lussac (1778-1850). In 1802, Charles and Gay-Lussac both proposed that for a fixed amount of gas at a constant pressure, the volume is directly proportional to its absolute temperature (V ∝ T). Figure below illustrates the volume-temperature relationship.	A: volume.
What material is transported in a process called longshore drift? Here are the choices: A. grass B. foods C. boats D. sediment	The transport of sediments by longshore currents is called longshore drift . Longshore drift is created in this way: Sediment is moved up the beach by an incoming wave. The wave approaches at an angle to the shore. Water then moves straight offshore. The sediment moves straight down the beach with it. The sediment is again picked up by a wave that is coming in at an angle. So longshore drift moves sediment along the shore. This zig-zag motion is pictured below ( Figure below ) and can also be seen at the link below.	D: sediment.
What has has revolutionized biological and biomedical research and applications? Here are the choices: A. polymerase chain reaction B. Compound chain reaction C. synthesis chain reaction D. organism chain reaction	Use a machine. The polymerase chain reaction has revolutionized biological and biomedical research and applications. Luckily many machines have been developed that allow this process to be performed rapidly and with precision.	A: polymerase chain reaction.
Electrons are organized into shells and subshells about the nucleus of this? Here are the choices: A. compound B. element C. atom D. molecule	Electrons are organized into shells and subshells about the nucleus of an atom.	C: atom.
What is the double-membrane structure that constitutes the outermost portion of the nucleus? Here are the choices: A. nuclear envelope B. energy fold C. energy envelope D. nuclear fold	The Nuclear Envelope The nuclear envelope is a double-membrane structure that constitutes the outermost portion of the nucleus ( Figure 4.11). Both the inner and outer membranes of the nuclear envelope are phospholipid bilayers. The nuclear envelope is punctuated with pores that control the passage of ions, molecules, and RNA between the nucleoplasm and cytoplasm. The nucleoplasm is the semi-solid fluid inside the nucleus, where we find the chromatin and the nucleolus. Chromatin and Chromosomes To understand chromatin, it is helpful to first consider chromosomes. Chromosomes are structures within the nucleus that are made up of DNA, the hereditary material. You may remember that in prokaryotes, DNA is organized into a single circular chromosome. In eukaryotes, chromosomes are linear structures. Every eukaryotic species has a specific number of chromosomes in the nuclei of its body’s cells. For example, in humans, the chromosome number is 46, while in fruit flies, it is eight. Chromosomes are only visible and distinguishable from one another when the cell is getting ready to divide. When the cell is in the growth and maintenance phases of its life cycle, proteins are attached to chromosomes, and they resemble an unwound, jumbled bunch of threads. These unwound protein-chromosome complexes are called chromatin ( Figure 4.12); chromatin describes the material that makes up the chromosomes both when condensed and decondensed.	A: nuclear envelope.
Each daughter cell represents one outcome of all possible combinations of maternal and paternal what? Here are the choices: A. chromosomes B. genes C. alleles D. traits		A: chromosomes.
What is the science of classifying the many organisms on earth called? Here are the choices: A. taxonomy B. general classification C. terminology D. methodology	The evolution of life on Earth over the past 4 billion years has resulted in a huge variety of species. For more than 2,000 years, humans have been trying to classify the great diversity of life. The science of classifying organisms is called taxonomy. Classification is an important step in understanding the present diversity and past evolutionary history of life on Earth.	A: taxonomy.
Platelets play a role in what cascade of reactions that converts plasma fibrinogen to fibrin? Here are the choices: A. sickle cell anemia B. blood clotting C. bleeding D. hemophilia		B: blood clotting.
What force includes forces of attraction and repulsion? Here are the choices: A. magnetic force B. molecular force C. gravitational force D. centripetal force	The force that a magnet exerts is called magnetic force. The force is exerted over a distance and includes forces of attraction and repulsion. A magnet can exert force over a distance because the magnet is surrounded by a magnetic field.	A: magnetic force.
How many atoms of oxygen does silicon dioxide contain? Here are the choices: A. six B. three C. two D. one	The name silicon dioxide implies one silicon atom and two oxygen atoms, so the formula is SiO2. We have a name that has numerical prefixes on both elements. Tri- means three, and tetrameans four, so the formula of this compound is Si3N4.	C: two.
A transformer has two coils, electrically insulated from each other. one coil is called the primary coil and the other is called the what? Here are the choices: A. quadratic coil B. young coil C. secondary coil D. tertiary coil	A transformer has two coils, electrically insulated from each other. One coil is called the primary coil and the other is called the secondary coil.	C: secondary coil.
What state of matter is characterized by tiny particles separated by large distances, which do not experience any force of attraction or repulsion with each other? Here are the choices: A. emissions B. steam C. gas D. liquids	Gases are composed of tiny particles that are separated by large distances. Gas particles are constantly moving, experiencing collisions with other gas particles and the walls of their container. The velocity of gas particles is related to the temperature of a gas. Gas particles do not experience any force of attraction or repulsion with each other.	C: gas.
Where are unsaturated fatty acids commonly found? Here are the choices: A. oil B. fish C. animal products D. butter	Unsaturated fatty acids have at least one double bond between carbon atoms. As a result, some carbon atoms are not bonded to as many hydrogen atoms as possible. They are unsaturated with hydrogens. Unsaturated fatty acids are found in oils.	A: oil.
Why is gingko biloba planted in public spaces? Here are the choices: A. self-containing B. resistant to pollution C. for xeriscaping D. self-pollinating	Gingkophytes The single surviving species of the gingkophytes group is the Gingko biloba (Figure 26.11). Its fan-shaped leaves—unique among seed plants because they feature a dichotomous venation pattern—turn yellow in autumn and fall from the tree. For centuries, G. biloba was cultivated by Chinese Buddhist monks in monasteries, which ensured its preservation. It is planted in public spaces because it is unusually resistant to pollution. Male and female organs are produced on separate plants. Typically, gardeners plant only male trees because the seeds produced by the female plant have an off-putting smell of rancid butter.	B: resistant to pollution.
What term means a representation of an object, system, or process? Here are the choices: A. icon B. model C. presentation D. pattern	A model is a representation of an object, system, or process. For example, a road map is a representation of an actual system of roads on the ground. Models are very useful in science. They provide a way to investigate things that are too small, large, complex, or distant to investigate directly. To be useful, a model must closely represent the real thing in important ways, but it must be simpler and easier to understand than the real thing.	B: model.
What makes metals shiny? Here are the choices: A. light expansion B. light characterization C. light energy D. light reflection	Metals are generally shiny. This is because they reflect much of the light that strikes them. The mercury pictured above is very shiny.	D: light reflection.
What are materials that have high resistance to electric current called? Here are the choices: A. motion reducers B. electric insulators C. power insulators D. cooling insulators	Materials that have high resistance to electric current are called electric insulators . Wood, rubber, and plastic are examples of electric insulators. Dry air is also an electric insulator.	B: electric insulators.
Which system in your body stores urine and is controlled by the nervous system? Here are the choices: A. urinary system B. muscular system C. cardiovascular system D. digestive system	The urinary system has roles you may be well aware of: cleansing the blood and ridding the body of wastes probably come to mind. However, there are additional, equally important functions played by the system. Take for example, regulation of pH, a function shared with the lungs and the buffers in the blood. Additionally, the regulation of blood pressure is a role shared with the heart and blood vessels. What about regulating the concentration of solutes in the blood? Did you know that the kidney is important in determining the concentration of red blood cells? Eighty-five percent of the erythropoietin (EPO) produced to stimulate red blood cell production is produced in the kidneys. The kidneys also perform the final synthesis step of vitamin D production, converting calcidiol to calcitriol, the active form of vitamin D. If the kidneys fail, these functions are compromised or lost altogether, with devastating effects on homeostasis. The affected individual might experience weakness, lethargy, shortness of breath, anemia, widespread edema (swelling), metabolic acidosis, rising potassium levels, heart arrhythmias, and more. Each of these functions is vital to your well-being and survival. The urinary system, controlled by the nervous system, also stores urine until a convenient time for disposal and then provides the anatomical structures to transport this waste liquid to the outside of the body. Failure of nervous control or the anatomical structures leading to a loss of control of urination results in a condition called incontinence. This chapter will help you to understand the anatomy of the urinary system and how it enables the physiologic functions critical to homeostasis. It is best to think of the kidney as a regulator of plasma makeup rather than simply a urine producer. As you read each section, ask yourself this question: “What happens if this does not work?” This question will help you to understand how the urinary system maintains homeostasis and affects all the other systems of the body and the quality of one’s life.	A: urinary system.
Which type of isomers generally have lower boiling and melting points than straight-chain isomers? Here are the choices: A. branched - solar isomers B. branched-chain isomers C. branched-looping isomers D. straight-chain isomers	Because isomers are different compounds, they have different properties. Generally, branched-chain isomers have lower boiling and melting points than straight-chain isomers. For example, the boiling and melting points of iso -butane are -12 °C and -160 °C, respectively, compared with 0 °C and -138 °C for n -butane. The more branching there is, the lower the boiling and melting points are.	B: branched-chain isomers.
Which temperature scale is commonly used in science? Here are the choices: A. centigrade B. kelvin scale C. celsius D. ph scale	one degree Fahrenheit. Only 100 Celsius degrees span the same range as 180 Fahrenheit degrees, thus one degree on the Celsius scale is 1.8 times larger than one degree on the Fahrenheit scale 180 / 100 = 9 / 5. The Kelvin scale is the temperature scale that is commonly used in science. It is an absolute temperature scale defined to have 0 K at the lowest possible temperature, called absolute zero. The official temperature unit on this scale is the kelvin, which is abbreviated K, and is not accompanied by a degree sign. The freezing and boiling points of water are 273.15 K and 373.15 K, respectively. Thus, the magnitude of temperature differences is the same in units of kelvins and degrees Celsius. Unlike other temperature scales, the Kelvin scale is an absolute scale. It is used extensively in scientific work because a number of physical quantities, such as the volume of an ideal gas, are directly related to absolute temperature. The kelvin is the SI unit used in scientific work.	B: kelvin scale.
What is required for both the synthesis and breakdown of molecules? Here are the choices: A. heating B. mixing C. energy D. sunlight	Introduction Virtually every task performed by living organisms requires energy. Energy is needed to perform heavy labor and exercise, but humans also use a great deal of energy while thinking, and even during sleep. In fact, the living cells of every organism constantly use energy. Nutrients and other molecules are imported, metabolized (broken down) and possibly synthesized into new molecules, modified if needed, transported around the cell, and may be distributed to the entire organism. For example, the large proteins that make up muscles are actively built from smaller molecules. Complex carbohydrates are broken down into simple sugars that the cell uses for energy. Just as energy is required to both build and demolish a building, energy is required for both the synthesis and breakdown of molecules. Additionally, signaling molecules such as hormones and neurotransmitters are transported between cells. Pathogenic bacteria and viruses are ingested and broken down by cells. Cells must also export waste and toxins to stay healthy, and many cells must swim or move surrounding materials via the beating motion of cellular appendages like cilia and flagella. The cellular processes listed above require a steady supply of energy. From where, and in what form, does this energy come? How do living cells obtain energy, and how do they use it? This chapter will discuss different forms of energy and the physical laws that govern energy transfer. This chapter will also describe how cells use energy and replenish it, and how chemical reactions in the cell are performed with great efficiency.	C: energy.
Parasites usually harm their hosts (or they wouldn't be parasites), but what do they usually stop short of doing? Here are the choices: A. reproducing with hosts B. benefiting their hosts C. mutating their hosts D. killing their host	Some parasites kill their host, but most do not. It’s easy to see why. If a parasite kills its host, the parasite may also die. Instead, parasites usually cause relatively minor damage to their host.	D: killing their host.
What basic structures are the site of all the life functions of an organism? Here are the choices: A. cells B. genes C. proteins D. lipids	all the life functions of an organism occur within cells,.	A: cells.
From where have the earliest ocean plants thought to have evolved? Here are the choices: A. green alga ancestor B. simple coral ancestor C. simple alga ancestor D. green pepinia ancestor	The earliest plants are thought to have evolved in the ocean from a green alga ancestor. Plants were among the earliest organisms to leave the water and colonize land. The evolution of vascular tissues allowed plants to grow larger and thrive on land. The evolution of seeds and pollen allowed them to reproduce on land without moisture. Flowering plants evolved flowers with ovaries that formed fruits. They have been the most successful plants of all.	A: green alga ancestor.
The liver has three main components: hepatocytes, bile canaliculi, and this? Here are the choices: A. hepatic sinusoids B. blood sinusoids C. tissue sinusoids D. coronary sinusoids	Histology The liver has three main components: hepatocytes, bile canaliculi, and hepatic sinusoids. A hepatocyte is the liver’s main cell type, accounting for around 80 percent of the liver's volume. These cells play a role in a wide variety of secretory, metabolic, and endocrine functions. Plates of hepatocytes called hepatic laminae radiate outward from the portal vein in each hepatic lobule. Between adjacent hepatocytes, grooves in the cell membranes provide room for each bile canaliculus (plural = canaliculi). These small ducts accumulate the bile produced by hepatocytes. From here, bile flows first into bile ductules and then into bile ducts. The bile ducts unite to form the larger right and left hepatic ducts, which themselves merge and exit the liver as the common hepatic duct. This duct then joins with the cystic duct from the gallbladder, forming the common bile duct through which bile flows into the small intestine. A hepatic sinusoid is an open, porous blood space formed by fenestrated capillaries from nutrient-rich hepatic portal veins and oxygen-rich hepatic arteries. Hepatocytes are tightly packed around the fenestrated endothelium of these spaces, giving them easy access to the blood. From their central position, hepatocytes process the nutrients, toxins, and waste materials carried by the blood. Materials such as bilirubin are processed and excreted into the bile canaliculi. Other materials including proteins, lipids, and carbohydrates are processed and secreted into the sinusoids or just stored in the cells until called upon. The hepatic sinusoids combine and send blood to a central vein. Blood then flows through a hepatic vein into the inferior vena cava. This means that blood and bile flow in opposite directions. The hepatic sinusoids also contain star-shaped reticuloendothelial cells (Kupffer cells), phagocytes that remove dead red and white blood cells, bacteria, and other foreign material that enter the sinusoids. The portal triad is a distinctive arrangement around the perimeter of hepatic lobules, consisting of three basic structures: a bile duct, a hepatic artery branch, and a hepatic portal vein branch.	A: hepatic sinusoids.
What bone is is one of a pair that together form the upper jaw, much of the hard palate, the medial floor of the orbit, and the lateral base of the nose? Here are the choices: A. mandibular bone B. nasal bone C. mastoid process D. maxillary bone	Maxillary Bone The maxillary bone, often referred to simply as the maxilla (plural = maxillae), is one of a pair that together form the upper jaw, much of the hard palate, the medial floor of the orbit, and the lateral base of the nose (see Figure 7.4). The curved, inferior margin of the maxillary bone that forms the upper jaw and contains the upper teeth is the alveolar process of the maxilla (Figure 7.14). Each tooth is anchored into a deep socket called an alveolus. On the anterior maxilla, just below the orbit, is the infraorbital foramen. This is the point of exit for a sensory nerve that supplies the nose, upper lip, and anterior cheek. On the inferior skull, the palatine process from each maxillary bone can be seen joining together at the midline to form the anterior three-quarters of the hard palate (see Figure 7.8a). The hard palate is the bony plate that forms the roof of the mouth and floor of the nasal cavity, separating the oral and nasal cavities.	D: maxillary bone.
When a rock is altered by heat from a nearby magma, what occurs? Here are the choices: A. form metamorphism B. evaporation C. sublimation D. contact metamorphism	Contact metamorphism occurs when a rock is altered by heat from a nearby magma.	D: contact metamorphism.
Which is one of the most complicated parts of gene regulation in eukaryotic cells? Here are the choices: A. start of transcription B. aftermath of transcription C. middle of transcription D. end of transcription	In eukaryotic cells, the start of transcription is one of the most complicated parts of gene regulation. There may be many regulatory proteins and regulatory elements involved. Regulation may also involve enhancers. Enhancers are distant regions of DNA that can loop back to interact with a gene’s promoter.	A: start of transcription.
How is thermal energy transferred in every-day, real life situations, such as holding a warm cup? Here are the choices: A. conduction B. decomposition C. oxidation D. condensation	A: Thermal energy is transferred by conduction from the hot iron to the shirt, from the hot cup to the hand holding it, from the flame of the camp stove to the bottom of the pot as well as from the bottom of the pot to the food inside, and from the feet to the snow. The shirt, hand, pot, food, and snow become warmer because of the transferred energy. Because the feet lose thermal energy, they feel colder.	A: conduction.
What consists of all the biotic and abiotic factors in an area and their interactions? Here are the choices: A. habitat B. ecosystem C. community D. macroevolution	An ecosystem consists of all the biotic and abiotic factors in an area and their interactions.	B: ecosystem.
What is the theory scientists use to explain the matter in the universe and how it's held together? Here are the choices: A. specific model B. organic model C. original model D. standard model	Based on their knowledge of subatomic particles, scientists have developed a theory called the standard model to explain all the matter in the universe and how it is held together. The model includes only the fundamental particles in the Table above . No other particles are needed to explain all kinds of matter. According to the model, all known matter consists of quarks and leptons that interact by exchanging bosons, which transmit fundamental forces. The standard model is a good theory because all of its predictions have been verified by experimental data. However, the model doesn’t explain everything, including the force of gravity and why matter has mass. Scientists continue to search for evidence that will allow them to explain these aspects of force and matter as well. You can learn much more about the standard model at the URL below. Click on “the standard model” and follow the sequence titled “What is fundamental?”.	D: standard model.
In what group of animals several forms of asexual reproduction are found? Here are the choices: A. invertebrates B. arthropods C. crustaceans D. insects		A: invertebrates.
After the amino acid molecule has been bound to its what, protein synthesis can take place? Here are the choices: A. trna carrier B. dna molecule C. RNA receptor D. base	How can a molecule containing just 4 different nucleotides specify the sequence of the 20 amino acids that occur in proteins? If each nucleotide coded for 1 amino acid, then obviously the nucleic acids could code for only 4 amino acids. What if amino acids were coded for by groups of 2 nucleotides? There are 42, or 16, different combinations of 2 nucleotides (AA, AU, AC, AG, UU, and so on). Such a code is more extensive but still not adequate to code for 20 amino acids. However, if the nucleotides are arranged in groups of 3, the number of different possible combinations is 43, or 64. Here we have a code that is extensive enough to direct the synthesis of the primary structure of a protein molecule. The genetic code can therefore be described as the identification of each group of three nucleotides and its particular amino acid. The sequence of these triplet groups in the mRNA dictates the sequence of the amino acids in the protein. Each individual three-nucleotide coding unit, as we have seen, is called a codon. Protein synthesis is accomplished by orderly interactions between mRNA and the other ribonucleic acids (transfer RNA [tRNA] and ribosomal RNA [rRNA]), the ribosome, and more than 100 enzymes. The mRNA formed in the nucleus during transcription is transported across the nuclear membrane into the cytoplasm to the ribosomes—carrying with it the genetic instructions. The process in which the information encoded in the mRNA is used to direct the sequencing of amino acids and thus ultimately to synthesize a protein is referred to as translation. Before an amino acid can be incorporated into a polypeptide chain, it must be attached to its unique tRNA. This crucial process requires an enzyme known as aminoacyl-tRNA synthetase (Figure 19.12 "Binding of an Amino Acid to Its tRNA"). There is a specific aminoacyl-tRNA synthetase for each amino acid. This high degree of specificity is vital to the incorporation of the correct amino acid into a protein. After the amino acid molecule has been bound to its tRNA carrier, protein synthesis can take place. Figure 19.13 "The Elongation Steps in Protein Synthesis" depicts a schematic stepwise representation of this all-important process. Figure 19.12 Binding of an Amino Acid to Its tRNA Saylor URL: http://www. saylor. org/books.	A: trna carrier.
The conversion of food that is consumed to nutrients involves what two major processes: Here are the choices: A. secrete and absorption B. absorption and excretion C. digestion and absorption D. untangling and absorption	16.2 \| Digestive System By the end of this section, you will be able to: • Explain the processes of digestion and absorption • Explain the specialized functions of the organs involved in processing food in the body • Describe the ways in which organs work together to digest food and absorb nutrients • Describe the essential nutrients required for cellular function that cannot be synthesized by the animal body • Describe how excess carbohydrates and energy are stored in the body All living organisms need nutrients to survive. While plants can obtain nutrients from their roots and the energy molecules required for cellular function through the process of photosynthesis, animals obtain their nutrients by the consumption of other organisms. At the cellular level, the biological molecules necessary for animal function are amino acids, lipid molecules, nucleotides, and simple sugars. However, the food consumed consists of protein, fat, and complex carbohydrates. Animals must convert these macromolecules into the simple molecules required for maintaining cellular function. The conversion of the food consumed to the nutrients required is a multistep process involving digestion and absorption. During digestion, food particles are broken down to smaller components, which are later absorbed by the body. This happens by both physical means, such as chewing, and by chemical means. One of the challenges in human nutrition is maintaining a balance between food intake, storage, and energy expenditure. Taking in more food energy than is used in activity leads to storage of the excess in the form of fat deposits. The rise in obesity and the resulting diseases like type 2 diabetes makes understanding the role of diet and nutrition in maintaining good health all the more important.	C: digestion and absorption.
What is the unsorted pile of material dropped by glaciers called? Here are the choices: A. glacial till B. icy deposit C. glacial runoff D. landfill		A: glacial till.
Each proton has how many units of positive charge? Here are the choices: A. two B. zero C. one D. three		C: one.
Because charges must have an unbroken path to follow, electric current cannot flow through a material unless it forms what? Here are the choices: A. closed loop B. total loop C. closed area D. complete loop	Look at the battery and light bulb in Figure below . The light bulb works and it’s connected to the battery, but it won’t light. The problem is the loose wire on the left. It must be connected to the positive terminal of the battery in order for the bulb to light up. The reason? Electric current can flow through a material such as a wire only if the material forms a closed loop. Charges must have an unbroken path to follow between the positively and negatively charged parts of the voltage source, in this case, the battery.	A: closed loop.
In living systems, diffusion of substances into and out of cells is mediated by the what membrane? Here are the choices: A. plasma B. gas C. fluid D. ferment	affect the rate of diffusion, including concentration gradient, size of the particles that are diffusing, temperature of the system, and so on. In living systems, diffusion of substances into and out of cells is mediated by the plasma membrane. Some materials diffuse readily through the membrane, but others are hindered, and their passage is made possible by specialized proteins, such as channels and transporters. The chemistry of living things occurs in aqueous solutions, and balancing the concentrations of those solutions is an ongoing problem. In living systems, diffusion of some substances would be slow or difficult without membrane proteins that facilitate transport.	A: plasma.
Ancient greeks mistook what simple sedentary animals for plants? Here are the choices: A. parasites B. sponges C. fungi D. corals		B: sponges.
What trimester is associated with rapid fetal growth? Here are the choices: A. fourth trimester B. second trimester C. third trimester D. first trimester	Figure 43.21 There is rapid fetal growth during the third trimester. (credit: modification of work by Gray’s Anatomy).	C: third trimester.
What are all scientific explanations and interpretations based on? Here are the choices: A. theories B. controls C. facts D. changes	All scientific explanations and interpretations are based on facts.	C: facts.
What is the process in which an atom becomes an ion known as? Here are the choices: A. oxidation B. electrification C. evaporation D. ionization	The process in which an atom becomes an ion is called ionization. It may occur when atoms are exposed to high levels of radiation. The radiation may give their outer electrons enough energy to escape from the attraction of the positive nucleus. However, most ions form when atoms transfer electrons to or from other atoms or molecules. For example, sodium atoms may transfer electrons to chlorine atoms. This forms positive sodium ions (Na + ) and negative chloride ions (Cl - ). You can see an animation of this process at the URL below.	D: ionization.
What are two examples of lipids? Here are the choices: A. vitamins and fatty acid B. adipose tissue and olive oil C. defects and oils D. fats and oils	Lipids are organic compounds such as fats and oils. They store energy and help form cell membranes in addition to having other functions in organisms.	D: fats and oils.
What can radioactive strontium replace in the human body making it dangerous? Here are the choices: A. magnesium B. calcium C. potassium D. oxygen	Radioactive strontium is dangerous because it can chemically replace calcium in the human body. The bones are particularly susceptible to radiation damage. Write the nuclear equation for the beta emission of strontium-90.	B: calcium.
Silicon with an element that gives it extra electrons is which type of semiconductor? Here are the choices: A. i.g - type B. m. Type C. k. - type D. n-type	An n-type (negative-type) semiconductor consists of silicon and an element such as phosphorus that gives the silicon crystal extra electrons. You can see this in the Figure above . An n-type semiconductor is like the negative terminal of a battery.	D: n-type.
Cold sores, influenza, and the common cold are all? Here are the choices: A. anal infections B. viral infections C. digestive infections D. trend infections		B: viral infections.
What helps to propel sponge larvae through the water? Here are the choices: A. antennae B. tentacles C. mucus D. cilia	Unlike sponge adults, sponge larvae can swim. They have cilia that propel them through the water. As larvae develop and grow, they become more similar to an adult sponge and lose their ability to swim.	D: cilia.
The majority of cells in blood are erythrocytes or? Here are the choices: A. Deep Blood Cells B. s.a blood cells C. red blood cells D. 50.3 blood cells	Primary Centers of the Immune System Although the immune system is characterized by circulating cells throughout the body, the regulation, maturation, and intercommunication of immune factors occur at specific sites. The blood circulates immune cells, proteins, and other factors through the body. Approximately 0.1 percent of all cells in the blood are leukocytes, which encompass monocytes (the precursor of macrophages) and lymphocytes. The majority of cells in the blood are erythrocytes (red blood cells). Lymph is a watery fluid that bathes tissues and organs with protective white blood cells and does not contain erythrocytes. Cells of the immune system can travel between the distinct lymphatic and blood circulatory systems, which are separated by interstitial space, by a process called extravasation (passing through to surrounding tissue). The cells of the immune system originate from hematopoietic stem cells in the bone marrow. Cytokines stimulate these stem cells to differentiate into immune cells. B cell maturation occurs in the bone marrow, whereas naïve T cells transit from the bone marrow to the thymus for maturation. In the thymus, immature T cells that express TCRs complementary to self-antigens are destroyed. This process helps prevent autoimmune responses. On maturation, T and B lymphocytes circulate to various destinations. Lymph nodes scattered throughout the body, as illustrated in Figure 42.20, house large populations of T and B cells, dendritic cells, and macrophages. Lymph gathers antigens as it drains from tissues. These antigens then are filtered through lymph nodes before the lymph is returned to circulation. APCs in the lymph nodes capture and process antigens and inform nearby lymphocytes about potential pathogens.	C: red blood cells.
Which gases trap heat in the atmosphere? Here are the choices: A. ozone B. methane and helium C. fluorine and nitrogen D. greenhouse	Greenhouse gases trap heat in the atmosphere. These gases include carbon dioxide, methane, water vapor, and ozone.	D: greenhouse.
The arrangement of what plant structures can be classified as either alternate, spiral, or opposite? Here are the choices: A. spores B. roots C. fruits D. leaves	Leaf Arrangement The arrangement of leaves on a stem is known as phyllotaxy. The number and placement of a plant’s leaves will vary depending on the species, with each species exhibiting a characteristic leaf arrangement. Leaves are classified as either alternate, spiral, or opposite. Plants that have only one leaf per node have leaves that are said to be either alternate—meaning the leaves alternate on each side of the stem in a flat plane—or spiral, meaning the leaves are arrayed in a spiral along the stem. In an opposite leaf arrangement, two leaves arise at the same point, with the leaves connecting opposite each other along the branch. If there are three or more leaves connected at a node, the leaf arrangement is classified as whorled.	D: leaves.
Acceleration is defined as the change in what over time? Here are the choices: A. volume B. direction C. mass D. velocity	What is the speed of the bird in Exercise 2.4? 6. Acceleration is the change in velocity over time. Given this information, is acceleration a vector or a scalar quantity? Explain. A weather forecast states that the temperature is predicted to be scalar quantity? Explain.	D: velocity.
Some protists absorb nutrients from decaying matter like a what? Here are the choices: A. insects B. mite C. fungus D. plant	Some protists absorb nutrients from decaying matter like a fungus.	C: fungus.
What noble gas follows hydrogen on the periodic table? Here are the choices: A. nitrogen B. helium C. oxygen D. halogen	Following hydrogen is the noble gas helium, which has an atomic number of 2. The helium atom contains two protons and two electrons. The first electron has the same four quantum numbers as the hydrogen atom electron (n = 1, l = 0, ml = 0, m s = + 1 ). The second electron also goes into the 1s orbital and fills that orbital. The second electron 2 has the same n, l, and ml quantum numbers, but must have the opposite spin quantum number, m s = − 1 . This is in 2 accord with the Pauli exclusion principle: No two electrons in the same atom can have the same set of four quantum numbers. For orbital diagrams, this means two arrows go in each box (representing two electrons in each orbital).	B: helium.
What is the order and family of a meat-eating cat like a tiger? Here are the choices: A. Synapsida felidae B. hierarchies felidae C. carnivora felidae D. Mammalia felidae	Most chordates are animals with backbones. These range from small fish to giant whales, from playful dogs to ferocious cats. Not nearly as diverse as the invertebrates. But chordates do have many amazing species. The white tiger ( Panthera tigris ) is a chordate. The tiger is also from the class Mammalia, order Carnivora, and family Felidae, meaning it is a meat-eating cat.	C: carnivora felidae.
What is required between cytoskeleton and motor proteins for cell motility? Here are the choices: A. inhibition B. absorption C. interaction D. translation		C: interaction.
Underground rock in a molten state is called? Here are the choices: A. magma B. gaseous C. igneous D. lava	A: It is always very hot deep underground where molten rock originates. The high temperatures give rock enough energy to melt and remain in a molten state. Underground rock in this state is called magma.	A: magma.
What takes over the synthesis and secretion of progesterone throughout pregnancy as the corpus luteum degenerates? Here are the choices: A. vagina B. placenta C. ovaries D. uterus	The placenta takes over the synthesis and secretion of progesterone throughout pregnancy as the corpus luteum degenerates. Like estrogen, progesterone suppresses FSH and LH. It also inhibits uterine contractions, protecting the fetus from preterm birth. This hormone decreases in late gestation, allowing uterine contractions to intensify and eventually progress to true labor. The placenta also produces hCG. In addition to promoting survival of the corpus luteum, hCG stimulates the male fetal gonads to secrete testosterone, which is essential for the development of the male reproductive system. The anterior pituitary enlarges and ramps up its hormone production during pregnancy, raising the levels of thyrotropin, prolactin, and adrenocorticotropic hormone (ACTH). Thyrotropin, in conjunction with placental hormones, increases the production of thyroid hormone, which raises the maternal metabolic rate. This can markedly augment a pregnant woman’s appetite and cause hot flashes. Prolactin stimulates enlargement of the mammary glands in preparation for milk production. ACTH stimulates maternal cortisol secretion, which contributes to fetal protein synthesis. In addition to the pituitary hormones, increased parathyroid levels mobilize calcium from maternal bones for fetal use.	B: placenta.
Distillation is an effective method to separate mixtures comprised of two or more what? Here are the choices: A. pure liquids B. ionic compounds C. elements D. solutes	Distillation is an effective method to separate mixtures comprised of two or more pure liquids. Distillation is a purification process in which the components of a liquid mixture are vaporized (transformed from liquid to gas) and then condensed (transformed from gas back to liquid) and isolated. In a simple distillation, a mixture is gradually heated. The solution with the lowest boiling point will change into a gas first. This gas, or vapor, then passes through a cooled tube (a condenser) where it condenses back into its liquid state. This condensed liquid is called the distillate. Figure below illustrates this.	A: pure liquids.
Aids is an infectious disease of which system? Here are the choices: A. digestion B. endocrine C. muscular D. immune	AIDS is an infectious disease of the immune system caused by a virus. Some diseases of the immune system are noninfectious. They include autoimmune diseases and allergies.	D: immune.
Where are the olfactory organs of snails located? Here are the choices: A. their anus B. their feet C. their shell D. their tentacles	Gastropods include snails and slugs. They use their foot to crawl. They have a well-developed head. There are many thousands of species of sea snails and sea slugs, as well as freshwater snails, freshwater limpets, land snails and land slugs. Gastropods live in many diverse habitats, from gardens to deserts and mountains. They also live in rivers, lakes and the ocean. Most shelled gastropods have a one-piece shell that is typically coiled or spiraled, but not all gastropods have shells. Gastropods have no sense of hearing, but they can see and have a keen sense of smell. In land-based gastropods, the olfactory organs (for smell) are the most important. These are located on the tentacles.	D: their tentacles.
What is the term for a pure substance that possesses unique properties and cannot be broken down into other substances? Here are the choices: A. plastic B. element C. alloy D. light	An element is pure substance that cannot be broken down into other substances. Each element has a particular set of properties that, taken together, distinguish it from all other elements. Table below lists the major elements in the human body. As you can see, you consist mainly of the elements oxygen, carbon, and hydrogen.	B: element.
What is the term for a cross in which the inheritance of two characteristics are tracked at the same time? Here are the choices: A. dihybrid cross B. identical twin C. Mendelian D. fraternal	After Mendel's first set of experiments, Mendel wanted to see if the inheritance of characteristics were dependent, or were they independent events. Mendel asked if the segregation of the heritable factors (allele) for one characteristic (gene) had any effect of the segregation of the factors for another characteristic. For example, did the segregation of the flower color factors have any effect on the segregation of the seed shape factors? So Mendel performed crosses in which he followed the segregation of two genes. Mendel crossed pea plants that differed in two characteristics, such as seed color and shape. A dihybrid cross is a cross in which the inheritance of two characteristics are tracked at the same time. The offspring of such a cross are called dihybrids .	A: dihybrid cross.
Through what system of the body do hormones generally travel? Here are the choices: A. circulatory system B. endocrine C. excretory D. respiratory		A: circulatory system.
What sort of digestion do animals engage in? Here are the choices: A. poison B. essential C. internal D. external	Virtually all animals have internal digestion of food. Animals consume other organisms and may use special tissues and organs to digest them. (Other heterotrophs, such as fungi, absorb nutrients directly from the environment. ).	C: internal.
What is the most abundant biochemical compound? Here are the choices: A. methane B. soil C. tissue D. cellulose	Cellulose is another complex carbohydrate found in plants that is a polymer of glucose. Cellulose molecules bundle together to form long, tough fibers. Cellulose is the most abundant biochemical compound. It makes up the cell walls of plants and gives support to stems and tree trunks.	D: cellulose.
When organisms penetrate a rock, they accelerate breakdown by chemical means and what other means? Here are the choices: A. geological B. temperature C. ecological D. mechanical		D: mechanical.

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