questions stringlengths 37 1.22k | reasoning stringlengths 0 3.56k ⌀ | answers stringlengths 4 138 |
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What is the low level of radiation that occurs naturally in the environment called?
Here are the choices:
A. temperature radiation
B. consequence radiation
C. neon radiation
D. background radiation | A low level of radiation occurs naturally in the environment. This is called background radiation. It comes from various sources. One source is rocks, which may contain small amounts of radioactive elements such as uranium. Another source is cosmic rays. These are charged particles that arrive on Earth from outer space. Background radiation is generally considered to be safe for living things. | D: background radiation. |
Varicella zoster virus causes what two illnesses?
Here are the choices:
A. syphilis and lyme
B. german measles and flu
C. chicken pox and shingles
D. flu and shingles | An enveloped virus. Varicella zoster virus causes chicken pox and shingles. | C: chicken pox and shingles. |
The urethra transports urine from what organ to the outside of the body for disposal?
Here are the choices:
A. lungs
B. brain
C. bladder
D. heart | Urethra The urethra transports urine from the bladder to the outside of the body for disposal. The urethra is the only urologic organ that shows any significant anatomic difference between males and females; all other urine transport structures are identical (Figure 25.3). | C: bladder. |
Magnetite crystals in lava typically point to what geographic location?
Here are the choices:
A. magnetic south pole
B. geographic north pole
C. the equator
D. magnetic north pole | Magnetite crystals in the lava point in the direction of the magnetic north pole. The different stripes of magnetic polarity reveal the different ages of the seafloor. | D: magnetic north pole. |
Liquids that mix with water in all proportions are usually polar substances or substances that form these?
Here are the choices:
A. hydrogen bonds
B. compressed bonds
C. atmospheric bonds
D. silicon bonds | Liquids that mix with water in all proportions are usually polar substances or substances that form hydrogen bonds. For such liquids, the dipole-dipole attractions (or hydrogen bonding) of the solute molecules with the solvent molecules are at least as strong as those between molecules in the pure solute or in the pure solvent. Hence, the two kinds of molecules mix easily. Likewise, nonpolar liquids are miscible with each other because there is no appreciable difference in the strengths of solute-solute, solvent-solvent, and solute-solvent intermolecular attractions. The solubility of polar molecules in polar solvents and of nonpolar molecules in nonpolar solvents is, again, an illustration of the chemical axiom “like dissolves like. ” Two liquids that do not mix to an appreciable extent are called immiscible. Layers are formed when we pour immiscible liquids into the same container. Gasoline, oil (Figure 11.15), benzene, carbon tetrachloride, some paints, and many other nonpolar liquids are immiscible with water. The attraction between the molecules of such nonpolar liquids and polar water molecules is ineffectively weak. The only strong attractions in such a mixture are between the water molecules, so they effectively squeeze out the molecules of the nonpolar liquid. The distinction between immiscibility and miscibility is really one of degrees, so that miscible liquids are of infinite mutual solubility, while liquids said to be immiscible are of very low (though not zero) mutual solubility. | A: hydrogen bonds. |
Lattice energy cannot be measured directly. what is its calculation based on?
Here are the choices:
A. measured energy changes
B. microscopic inspection
C. change in temperature
D. chemical reactions | There are a number of different ways to measure the strength of a given crystal lattice. One way would be to measure the amount of energy needed to completely pull apart an ionic substance into isolated ions. This value, known as the lattice energy , cannot be measured directly, but it can be calculated based on measured energy changes for other more feasible processes. The lattice energy of an ionic solid provides us with one way to measure the relative strength of the ionic bonds in that compound. Table below shows the lattice energies for various ionic substances:. | A: measured energy changes. |
What process provides over 99% of the energy supply for life on earth?
Here are the choices:
A. photosynthesis
B. nutrients
C. Carbon
D. gases | Photosynthesis provides over 99% of the energy supply for life on Earth. A much smaller group of autotrophs - mostly bacteria in dark or low-oxygen environments - produce food using the chemical energy stored in inorganic molecules such as hydrogen sulfide, ammonia, or methane. While photosynthesis transforms light energy to chemical energy, this alternate method of making food transfers chemical energy from inorganic to organic molecules. It is therefore called chemosynthesis , and is characteristic of the tubeworms shown in Figure below . Some of the most recently discovered chemosynthetic bacteria inhabit deep ocean hot water vents or “black smokers. ” There, they use the energy in gases from the Earth’s interior to produce food for a variety of unique heterotrophs: giant tube worms, blind shrimp, giant white crabs, and armored snails. Some scientists think that chemosynthesis may support life below the surface of Mars, Jupiter's moon, Europa, and other planets as well. Ecosystems based on chemosynthesis may seem rare and exotic, but they too illustrate the absolute dependence of heterotrophs on autotrophs for food. | A: photosynthesis. |
What type of animal are most reptiles in regards to diet?
Here are the choices:
A. arthropods
B. herbivores
C. omnivores
D. carnivores | Most reptiles are carnivores, and large reptiles are the top predators in their ecosystems. | D: carnivores. |
Because of their reactivity, we do not find most representative metals as free elements where?
Here are the choices:
A. in nature
B. in water
C. underground
D. in the atomospher | [PCl 3][Cl 2] (0.135)(0.135) = = 0.021 0.87 [PCl 5] The equilibrium constant calculated from the equilibrium concentrations is equal to the value of Kc given in the problem (when rounded to the proper number of significant figures). Thus, the calculated equilibrium concentrations check. Kc =. | A: in nature. |
Two important concepts, niche and habitat, are associated with what?
Here are the choices:
A. natural selection
B. water
C. ecosystem
D. plant | Two important concepts associated with the ecosystem are niche and habitat. | C: ecosystem. |
When does diseases like alzheimer's become more common?
Here are the choices:
A. toddler
B. i-40 age
C. teenager
D. old age | Old age begins in the mid-60s and lasts until the end of life. Most people over 65 have retired from work, freeing up their time for hobbies, grandchildren, and other interests. Stamina, strength, reflex time, and the senses all decline during old age, and the number of brain cells decreases as well. The immune system becomes less efficient, increasing the risk of serious illnesses such as cancer and pneumonia. Diseases such as Alzheimer’s disease that cause loss of mental function also become more common. | D: old age. |
What is a fibrocartilaginous pad that fills the gap between adjacent vertebral bodies?
Here are the choices:
A. Back Disk
B. unidirectional disc
C. subsidence disc
D. intervertebral disc | Intervertebral Disc An intervertebral disc is a fibrocartilaginous pad that fills the gap between adjacent vertebral bodies (see Figure 7.24). Each disc is anchored to the bodies of its adjacent vertebrae, thus strongly uniting these. The discs also provide padding between vertebrae during weight bearing. Because of this, intervertebral discs are thin in the cervical region and thickest in the lumbar region, which carries the most body weight. In total, the intervertebral discs account for approximately 25 percent of your body height between the top of the pelvis and the base of the skull. Intervertebral discs are also flexible and can change shape to allow for movements of the vertebral column. Each intervertebral disc consists of two parts. The anulus fibrosus is the tough, fibrous outer layer of the disc. It forms a circle (anulus = “ring” or “circle”) and is firmly anchored to the outer margins of the adjacent vertebral bodies. Inside is the nucleus pulposus, consisting of a softer, more gel-like material. It has a high water content that serves to resist compression and thus is important for weight bearing. With increasing age, the water content of the nucleus pulposus gradually declines. This causes the disc to become thinner, decreasing total body height somewhat, and reduces the flexibility and range of motion of the disc, making bending more difficult. The gel-like nature of the nucleus pulposus also allows the intervertebral disc to change shape as one vertebra rocks side to side or forward and back in relation to its neighbors during movements of the vertebral column. Thus, bending forward causes compression of the anterior portion of the disc but expansion of the posterior disc. If the posterior anulus fibrosus is weakened due to injury or increasing age, the pressure exerted on the disc when bending forward and lifting a heavy object can cause the nucleus pulposus to protrude posteriorly through the anulus fibrosus, resulting in a herniated disc (“ruptured” or “slipped” disc) (Figure 7.30). The posterior bulging of the nucleus pulposus can cause compression of a spinal nerve at the point where it exits through the intervertebral foramen, with resulting pain and/or muscle weakness in those body regions supplied by that nerve. The most common sites for disc herniation are the L4/L5 or L5/S1 intervertebral discs, which can cause sciatica, a widespread pain that radiates from the lower back down the thigh and into the leg. Similar injuries of the C5/C6 or C6/C7 intervertebral discs, following forcible hyperflexion of the neck from a collision accident or football injury, can produce pain in the neck, shoulder, and upper limb. | D: intervertebral disc. |
What organic catalysts work by lowering the activation energy needed to start biochemical reactions?
Here are the choices:
A. carbohydrates
B. glucose
C. enzymes
D. hormones | Enzymes work by lowering the activation energy needed to start biochemical reactions. | C: enzymes. |
What structure supports the body, protects internal organs, produces blood cells, and maintains mineral homeostasis?
Here are the choices:
A. fossil
B. cuticle
C. skin
D. skeleton | The skeleton supports the body, protects internal organs, produces blood cells, and maintains mineral homeostasis. | D: skeleton. |
When vertebrate animals metabolize ammonia what is the primary byproduct that is produced?
Here are the choices:
A. carbon monoxide
B. urea
C. proteins
D. dioxide | 41.4 Nitrogenous Wastes Ammonia is the waste produced by metabolism of nitrogen-containing compounds like proteins and nucleic acids. While aquatic animals can easily excrete ammonia into their watery surroundings, terrestrial animals have evolved special mechanisms to eliminate the toxic ammonia from their systems. Urea is the major byproduct of ammonia metabolism in vertebrate animals. Uric acid is the major byproduct of ammonia metabolism in birds, terrestrial arthropods, and reptiles. | B: urea. |
Which process involves solvent separation on a solid medium?
Here are the choices:
A. substration
B. resonance
C. affinity
D. chromatography | Chromatography involves solvent separation on a solid medium. | D: chromatography. |
Plasmodesmata and gap junctions are channels between adjacent cells of what respective types?
Here are the choices:
A. plant and fungus
B. plant and animal
C. healthy and sick
D. new and old | 4.6 Connections between Cells and Cellular Activities Animal cells communicate via their extracellular matrices and are connected to each other via tight junctions, desmosomes, and gap junctions. Plant cells are connected and communicate with each other via plasmodesmata. When protein receptors on the surface of the plasma membrane of an animal cell bind to a substance in the extracellular matrix, a chain of reactions begins that changes activities taking place within the cell. Plasmodesmata are channels between adjacent plant cells, while gap junctions are channels between adjacent animal cells. However, their structures are quite different. A tight junction is a watertight seal between two adjacent cells, while a desmosome acts like a spot weld. | B: plant and animal. |
Natural gas burns cleaner and produces less carbon dioxide than fuels of what type?
Here are the choices:
A. fossil fuels
B. biofuels
C. renewable fuels
D. solar energy | Natural gas burns cleaner than other fossil fuels. As a result, it causes less air pollution. It also produces less carbon dioxide than the other fossil fuels. Because it burns cleaner than other fossil fuels, natural gas has a good reputation. Still, natural gas does emit pollutants. | A: fossil fuels. |
What are the simplest types of carbon-based compounds?
Here are the choices:
A. Cells
B. particles
C. hydrocarbons
D. Microbes | Hydrocarbons are compounds that contain only carbon and hydrogen. They are the simplest type of carbon-based compounds. | C: hydrocarbons. |
What process moves food through the esophagus no matter which position the body is in?
Here are the choices:
A. homeostasis
B. mastication
C. proteolysis
D. peristalsis | Some people think that gravity moves food through the esophagus. If that were true, food would move through the esophagus only when you are sitting or standing upright. In fact, because of peristalsis, food can move through the esophagus no matter what position you are in—even upside down! Just don’t try to swallow food when you are upside down—you could choke!. | D: peristalsis. |
The female reproductive organs include the ovaries, fallopian tubes, uterus, and what?
Here are the choices:
A. intestines
B. womb
C. bladder
D. vagina | The female reproductive organs include the ovaries, fallopian tubes, uterus, and vagina. | D: vagina. |
What do offsprings obtain from their parents in what is called, inheritance?
Here are the choices:
A. characteristics
B. variations
C. attributes
D. mutations | A: characteristics. | |
Warming up your body before a workout does what to the blood flow?
Here are the choices:
A. increases it
B. reduces it
C. stops it
D. minimizes it | Sometimes muscles and tendons get injured when a person starts doing an activity before they have warmed up properly. A warm up is a slow increase in the intensity of a physical activity that prepares muscles for an activity. Warming up increases the blood flow to the muscles and increases the heart rate. Warmed-up muscles and tendons are less likely to get injured. For example, before running or playing soccer, a person might jog slowly to warm muscles and increase their heart rate. Even elite athletes need to warm up ( Figure below ). | A: increases it. |
What is a substance that increases the hydrogen ion concentration of a solution?
Here are the choices:
A. carbon
B. sulfur
C. base
D. acid | D: acid. | |
Scientists ask questions, and then make detailed observations to try to ask more specific questions, in order to develop what?
Here are the choices:
A. suggests
B. theories
C. hypothesis
D. Tests | A scientist is always trying to find the truth and discover new truths. How can you think like a scientist? Thinking like a scientist is based on asking and answering questions. Though you may not know it, you do this all day long. Scientists ask questions, and then make detailed observations to try to ask more specific questions and develop a hypothesis . They may design and perform an experiment to try to answer their question and test their hypothesis. From the results of their experiment, scientists draw conclusions . A conclusion describes what the evidence tells the scientist. | C: hypothesis. |
What is the main difference between prokaryotic or eukaryotic cells ?
Here are the choices:
A. the presence of a Golgi Apparatus
B. the presence of cell walls
C. the type of metabolic waste
D. the presence of a nucleus | The answer depends on if the cell is prokaryotic or eukaryotic. The main difference between the two types of cells is the presence of a nucleus. And in eukaryotic cells, DNA lives in the nucleus. | D: the presence of a nucleus. |
Supercontinents have formed at least how many times in earth history?
Here are the choices:
A. nine
B. twenty
C. five
D. two | The first continents were small but they grew over time. Supercontinents have formed at least five times in Earth history. | C: five. |
How are layers of the atmosphere divided?
Here are the choices:
A. temperature gradients
B. density gradients
C. air gradients
D. color gradients | The layers of the atmosphere are divided by their temperature gradients. The lowest layer is the troposphere. All weather takes place in this layer. The next layer is the stratosphere. The stratosphere contains the protective ozone layer. More sunlight strikes at the Equator than at the poles. This is what drives the global winds. Warm air rises, moves poleward, and then sinks when it meets with air moving toward the Equator. The result is six atmospheric circulation cells around the world. There are three cells in each hemisphere. Pollutants enter the atmosphere from a few sources. The most important is fossil fuel burning. Air pollution has bad effects on the environment and on human health. By reducing fossil fuel use we can make the environment cleaner. When ozone depletion was found to be a problem, the world acted. As a result, the ozone hole has stabilized. The hole will be getting smaller over the next decades. | A: temperature gradients. |
What term is used to describe molecules that contain carbon-nitrogen bonds?
Here are the choices:
A. compounds
B. ions
C. nitrites
D. amines | Amines are molecules that contain carbon-nitrogen bonds. The nitrogen atom in an amine has a lone pair of electrons and three bonds to other atoms, either carbon or hydrogen. Various nomenclatures are used to derive names for amines, but all involve the class-identifying suffix –ine as illustrated here for a few simple examples:. | D: amines. |
Birds have a flow-through respiratory system in which air flows unidirectionally from the posterior sacs into the lungs, then into these?
Here are the choices:
A. alveoli
B. gills
C. anterior air sacs
D. posterior bronchi | Figure 39.14 (a) Birds have a flow-through respiratory system in which air flows unidirectionally from the posterior sacs into the lungs, then into the anterior air sacs. The air sacs connect to openings in hollow bones. (b) Dinosaurs, from which birds descended, have similar hollow bones and are believed to have had a similar respiratory system. (credit b: modification of work by Zina Deretsky, National Science Foundation). | C: anterior air sacs. |
What are convection currents that occur far below the surface of the ocean called?
Here are the choices:
A. waves
B. subsequent currents
C. flat currents
D. deep currents | Deep currents are convection currents that occur far below the surface. They are caused by differences in the density of ocean water. | D: deep currents. |
Cations are attracted to anions, which are ions with what charge?
Here are the choices:
A. positive
B. neutral
C. negative
D. similar | 2.2 Chemical Bonds Each moment of life, atoms of oxygen, carbon, hydrogen, and the other elements of the human body are making and breaking chemical bonds. Ions are charged atoms that form when an atom donates or accepts one or more negatively charged electrons. Cations (ions with a positive charge) are attracted to anions (ions with a negative charge). This attraction is called an ionic bond. In covalent bonds, the participating atoms do not lose or gain electrons, but rather share them. Molecules with nonpolar covalent bonds are electrically balanced, and have a linear three-dimensional shape. Molecules with polar covalent bonds have “poles”—regions of weakly positive and negative charge—and have a triangular three-dimensional shape. An atom of oxygen and two atoms of hydrogen form water molecules by means of polar covalent bonds. Hydrogen bonds link hydrogen atoms already participating in polar covalent bonds to anions or electronegative regions of other polar molecules. Hydrogen bonds link water molecules, resulting in the properties of water that are important to living things. | C: negative. |
A non-bony skeleton that forms outside of the body is known as a what?
Here are the choices:
A. endoskeleton
B. exoplate
C. excitoskeleton
D. exoskeleton | One way early land invertebrates solved these problems was with an exoskeleton. This is a non-bony skeleton that forms on the outside of the body. It supports the body and helps it retain water. As the organism grows, it sheds its old exoskeleton and grows a new one. Figure below shows the discarded exoskeleton of a dragonfly. | D: exoskeleton. |
The vagina connects to which internal organ?
Here are the choices:
A. ovaries
B. uterus
C. valves
D. artery | The vagina is a cylinder-shaped organ found inside of the female body. One end of the vagina opens at the outside of the body. The other end joins with the uterus. During sexual intercourse, sperm may be released into the vagina. If this occurs, the sperm will move through the vagina and into the uterus. During birth, a baby passes from the uterus to the vagina to leave the body. | B: uterus. |
What is the measure of electric current?
Here are the choices:
A. ampheres
B. volts
C. intensity
D. watts | One advantage of anaerobic respiration is obvious. It lets organisms live in places where there is little or no oxygen. Such places include deep water, soil, and the digestive tracts of animals such as humans (see Figure below ). | A: ampheres. |
Name a passageway that is shared with the digestive system.
Here are the choices:
A. trachea
B. larynx
C. pharynx
D. esophagus | Next, air passes through the pharynx, a passageway that is shared with the digestive system. From the pharynx, the air passes next through the larynx, or voice box. | C: pharynx. |
What substances function as a long-term energy store in the human body and possess long carbon chains that prevent dissolving in water?
Here are the choices:
A. nanoparticles
B. steroids
C. triglycerides
D. hydrocarbons | Triglycerides function as a long-term storage form of energy in the human body. Because of the long carbon chains, triglycerides are nearly nonpolar molecules and thus do not dissolve readily in polar solvents such as water. Instead, oils and fats are soluble in nonpolar organic solvents such as hexane and ethers. | C: triglycerides. |
Thermal, radiant, electrical, nuclear, and chemical are all types of what?
Here are the choices:
A. fuel
B. fuel
C. energy
D. heating | The chapter describes thermal energy, radiant energy, electrical energy, nuclear energy, and chemical energy. Which form(s) of energy are represented by each of the following?. | C: energy. |
Coronary arteries ans small in what?
Here are the choices:
A. diameter
B. density
C. height
D. length | A: diameter. | |
What occurs when a substance reacts quickly with oxygen?
Here are the choices:
A. oxidation
B. combustion reaction
C. convection
D. catalytic conversion | A combustion reaction occurs when a substance reacts quickly with oxygen (O 2 ). You can see an example of a combustion reaction in Figure below . Combustion is commonly called burning. The substance that burns is usually referred to as fuel. The products of a combustion reaction include carbon dioxide (CO 2 ) and water (H 2 O). The reaction typically gives off heat and light as well. The general equation for a combustion reaction can be represented by:. | B: combustion reaction. |
What are the two basic types of competition called?
Here are the choices:
A. exploitative and beneficial
B. instraspecifc and interspecific
C. weak and strong
D. interference and interaction | Aggressive behavior often occurs when individuals compete for the same resources. Animals may compete for territory, water, food, or mates. There are two basic types of competition: intraspecific and interspecific. | B: instraspecifc and interspecific. |
Algae are much simpler than protozoa. they are aquatic and contain this?
Here are the choices:
A. testes
B. cloning factor
C. chlorophyll
D. sporozoa | 22.11 Algae Algae are much simpler than protozoa. They are aquatic and contain chlorophyll. Algae can exist as a single cell or as giant seaweeds 60 m in length. Formerly, algae were classified as plants but this was incorrect as algae lack parts of true plants: leaves, stems, roots, xylem, and phloem. Since algae belong in the kingdom Protista, algae is a broad term used to denote all aquatic eukaryotes which photosynthesise; algae can differ in size and shape as well. There are six phyla of algae:chlorophytes (green algae), phaeophytes (brown algae), rhodophytes (red algae), chrysophytes (diatoms), pyrrophytes (dinoflagellates), and euglenophytes (euglenoids). | C: chlorophyll. |
What is a gram stain used to identify ?
Here are the choices:
A. different types of bacteria
B. radioactivity
C. acids or bases
D. different types of liquids | Different types of bacteria stain a different color when Gram stain is applied to them. This makes them easy to identify. Some stain purple and some stain red, as you can see in Figure below . The two types differ in their outer layers. This explains why they stain differently. | A: different types of bacteria. |
Burning gas to run our cars is an example of how human activity is contributing to what global event?
Here are the choices:
A. ozone change
B. climate change
C. metamorphic change
D. carbon change | Flickr:futureatlas. com (http://futureatlas. com/blog/). Human activities like burning gasoline in cars are contributing to a global change in our climate . CC BY 2.0. | B: climate change. |
The periodic table of elements is divided into what?
Here are the choices:
A. groups
B. spheres
C. patterns
D. squares | Each element has its own square in the periodic table. The square contains the chemical symbol for the element, the atomic number, and the atomic weight . The atomic weight of an element is a weighted average of its isotopes. | D: squares. |
Wave amplitude of a transverse wave is the difference in height between what and the resting position?
Here are the choices:
A. a magnitude
B. a valley
C. a crest
D. a cascade | Wave amplitude of a transverse wave is the difference in height between a crest and the resting position. Wave amplitude of a longitudinal wave is the distance between particles of the medium where it is compressed by the wave. | C: a crest. |
What is secreted before ejaculation to neutralize acidic urine remaining in the urethra?
Here are the choices:
A. sperm
B. pre-cum
C. semen
D. clear mucus | D: clear mucus. | |
Because conifers carry both male and female sporophylls on the same mature sporophyte, they are considered what type of plant?
Here are the choices:
A. bioecious
B. dioecious
C. monoecious
D. siliceous | Life Cycle of a Conifer Pine trees are conifers (cone bearing) and carry both male and female sporophylls on the same mature sporophyte. Therefore, they are monoecious plants. Like all gymnosperms, pines are heterosporous and generate two different types of spores: male microspores and female megaspores. In the male cones, or staminate cones, the microsporocytes give rise to pollen grains by meiosis. In the spring, large amounts of yellow pollen are released and carried by the wind. Some gametophytes will land on a female cone. Pollination is defined as the initiation of pollen tube growth. The pollen tube develops slowly, and the generative cell in the pollen grain divides into two haploid sperm cells by mitosis. At fertilization, one of the sperm cells will finally unite its haploid nucleus with the haploid nucleus of a haploid egg cell. Female cones, or ovulate cones, contain two ovules per scale. One megaspore mother cell, or megasporocyte, undergoes meiosis in each ovule. Three of the four cells break down; only a single surviving cell will develop into a female multicellular gametophyte, which encloses archegonia (an archegonium is a reproductive organ that contains a single large egg). Upon fertilization, the diploid egg will give rise to the embryo, which is enclosed in a seed coat of tissue from the parent plant. Fertilization and seed development is a long process in pine trees: it may take up to two years after pollination. The seed that is formed contains three generations of tissues: the seed coat that originates from the sporophyte tissue, the gametophyte that will provide nutrients, and the embryo itself. | C: monoecious. |
Who lack some of the defining traits of chordates?
Here are the choices:
A. adult humans
B. Reptiles
C. Adult Mammals
D. Childern | Adult humans lack some of the defining traits of chordates. Why are humans still classified in the chordate phylum?. | A: adult humans. |
What does convection within the earth's mantel cause?
Here are the choices:
A. volcanos
B. microorganisms to move
C. plates to move
D. hurricanes | Convection within the Earth’s mantle causes the plates to move. Mantle material is heated above the core. The hot mantle rises up towards the surface ( Figure below ). As the mantle rises it cools. At the surface the material moves horizontally away from a mid-ocean ridge crest. The material continues to cool. It sinks back down into the mantle at a deep sea trench. The material sinks back down to the core. It moves horizontally again, completing a convection cell. | C: plates to move. |
Autoimmunity can develop with time, and its causes may be rooted in this?
Here are the choices:
A. resistance
B. molecular mimicry
C. inheritance
D. spontaneous mutation | Autoimmunity can develop with time, and its causes may be rooted in molecular mimicry. Antibodies and TCRs may bind self antigens that are structurally similar to pathogen antigens, which the immune receptors first raised. As an example, infection with Streptococcus pyogenes (bacterium that causes strep throat) may generate antibodies or T cells that react with heart muscle, which has a similar structure to the surface of S. pyogenes. These antibodies can damage heart muscle with autoimmune attacks, leading to rheumatic fever. Insulin-dependent (Type 1) diabetes mellitus arises from a destructive inflammatory TH1 response against insulin-producing cells of the pancreas. Patients with this autoimmunity must be injected with insulin that originates from other sources. | B: molecular mimicry. |
Why does warm air rise higher in the troposphere?
Here are the choices:
A. it is more dense than cool air
B. it is less flourishing than cool air
C. it is less dense than cool air
D. It contains hydrogen | Air in the troposphere is warmer closer to Earth’s surface. Warm air is less dense than cool air, so it rises higher in the troposphere. This starts a convection cell. Convection mixes the air in the troposphere. Rising air is also a main cause of weather. All of Earth’s weather takes place in the troposphere. | C: it is less dense than cool air. |
Getting the same result when an experiment is repeated is called what?
Here are the choices:
A. mutation
B. initiation
C. replication
D. repetition | Scientists also have to “check their work. ” The results of an investigation are not likely to be well accepted unless the investigation is repeated—usually many times—and the same result is always obtained. Getting the same result when an experiment is repeated is called replication . If research results can be replicated, it means they are more likely to be correct. Repeated replication of investigations may turn a hypothesis into a theory. On the other hand, if results cannot be replicated they are likely to be incorrect. | C: replication. |
Some membranes have what kind of surfaces exposed to the cytoplasm?
Here are the choices:
A. outer
B. hydrophobic
C. bilayer
D. obstructionary | B: hydrophobic. | |
Plants and fungi cells have what basic cell structure, which animals do not have?
Here are the choices:
A. Cell Membrane
B. Lysosomes
C. Cytoskeleton
D. cell wall | Plants and fungi cells both have a cell wall, which animals do not have. | D: cell wall. |
The way in which the sun produces light is called what?
Here are the choices:
A. rays
B. photosynthesis
C. tumescence
D. incandescence | Most of the visible light on Earth comes from the sun. The sun and other stars produce light because they are so hot. They glow with light due to their extremely high temperatures. This way of producing light is called incandescence . Incandescent light bulbs also produce light in this way. When electric current passes through a wire filament inside an incandescent bulb, the wire gets so hot that it glows. Do you see the glowing filament inside the incandescent light bulb in the Figure below ?. | D: incandescence. |
What kind of light bulb contains a thin wire filament made of tungsten that gets hot and glows?
Here are the choices:
A. fluorescent
B. LED
C. black light
D. incandescent | An incandescent light bulb produces visible light by incandescence. The bulb contains a thin wire filament made of tungsten. When electric current passes through the filament, it gets extremely hot and glows. You can learn more about incandescent light bulbs at the URL below. | D: incandescent. |
What do you call a mixture in which some particles settle out of it when it is left standing?
Here are the choices:
A. alloy
B. emulsion
C. homogenous
D. suspension | A suspension is a heterogeneous mixture in which some of the particles settle out of the mixture upon standing. The particles in a suspension are far larger than those of a solution and thus gravity is able to pull them down out of the dispersion medium (water). The typical diameter for the dispersed particles (the sand) of a suspension is about 1000 times greater than those of a solution (less than approximately two nanometers for particles in solution, compared to greater than 1000 nanometers for particles in suspension). Unlike in a solution, the dispersed particles can be separated from the dispersion medium by filtering. Suspensions are heterogeneous because at least two different substances in the mixture can be identified. | D: suspension. |
What do you call the process of a solid becoming a liquid?
Here are the choices:
A. freezing
B. vaporizing
C. boiling
D. melting | Substances can change phase—often because of a temperature change. At low temperatures, most substances are solid; as the temperature increases, they become liquid; at higher temperatures still, they become gaseous. The process of a solid becoming a liquid is called melting (an older term that you may see sometimes is fusion). The opposite process, a liquid becoming a solid, is called solidification. For any pure substance, the temperature at which melting occurs—known as the melting point—is a characteristic of that substance. It requires energy for a solid to melt into a liquid. Every pure substance has a certain amount of energy it needs to change from a solid to a liquid. This amount is called theenthalpy of fusion (or heat of fusion) of the substance, represented as ΔHfus. Some ΔHfus values are listed in Table 10.2 "Enthalpies of Fusion for Various Substances"; it is assumed that these values are for the melting point of the substance. Note that the unit of ΔHfus is kilojoules per mole, so we need to know the quantity of material to know how much energy is involved. The ΔHfus is always tabulated as a positive number. However, it can be used for both the melting and the solidification processes as long as you keep in mind that melting is always endothermic (so ΔH will be positive), while solidification is always exothermic (so ΔH will be negative). Table 10.2 Enthalpies of Fusion for Various Substances Substance (Melting Point). | D: melting. |
Once a plant cell becomes specialized, what can they no longer do?
Here are the choices:
A. cellular respiration
B. osmosis
C. photosynthesis
D. divide | As plant cells grow, they also become specialized into different cell types. Once cells become specialized, they can no longer divide. So how do plants grow after that? The key to continued growth is meristem. Meristem is a type of plant tissue consisting of undifferentiated cells that can continue to divide. | D: divide. |
The hardest natural substance, diamond is a form of what element?
Here are the choices:
A. hydrogen
B. zenon
C. zirconium
D. carbon | Diamond is a form of carbon in which each carbon atom is covalently bonded to four other carbon atoms. This forms a strong, rigid, three-dimensional structure (see Figure below ). Diamond is the hardest natural substance, and no other natural substance can scratch it. This property makes diamonds useful for cutting and grinding tools as well as for rings and other jewelry (see Figure below ). | D: carbon. |
Much of what type of radiation that strikes the planet is reflected back into space?
Here are the choices:
A. solar radiation
B. magentic radiation
C. microwaves
D. gamma rays | A: solar radiation. | |
What particles are formed from a neutron in beta decay?
Here are the choices:
A. electron and a proton
B. mucus and a proton
C. rust and proton
D. atom and proton | In beta decay, an electron and a proton form from a neutron (another unusual particle, called an antineutrino, is also produced). Only the electron is emitted from the nucleus. How does this change the atomic number and atomic mass of the atom?. | A: electron and a proton. |
What class of acids do carboxylic acids fall under?
Here are the choices:
A. carbolic acids
B. inorganic acids
C. organic acids
D. hydrochloric acids | Common acids and the polyatomic anions derived from them have their own names and rules for nomenclature. The nomenclature of acids differentiates between oxoacids, in which the H+ ion is attached to an oxygen atom of a polyatomic ion, and acids in which the H + ion is attached to another element. Carboxylic acids are an important class of organic acids. Ammonia is an important base, as are its organic derivatives, the amines. | C: organic acids. |
Plants can absorb inorganic nutrients and water through their root system, and what gas from the environment?
Here are the choices:
A. nitrogen dioxide
B. carbon dioxide
C. hydrogen dioxide
D. chemical dioxide | CHAPTER SUMMARY 31.1 Nutritional Requirements of Plants Plants can absorb inorganic nutrients and water through their root system, and carbon dioxide from the environment. The combination of organic compounds, along with water, carbon dioxide, and sunlight, produce the energy that allows plants to grow. Inorganic compounds form the majority of the soil solution. Plants access water though the soil. Water is absorbed by the plant root, transports nutrients throughout the plant, and maintains the structure of the plant. Essential elements are indispensable elements for plant growth. They are divided into macronutrients and micronutrients. The macronutrients plants require are carbon, nitrogen, hydrogen, oxygen, phosphorus, potassium, calcium, magnesium, and sulfur. Important micronutrients include iron, manganese, boron, molybdenum, copper, zinc, chlorine, nickel, cobalt, silicon and sodium. | B: carbon dioxide. |
Giardia is an example of a protozoa that uses flagella for what purpose?
Here are the choices:
A. light
B. nutrients
C. reproduction
D. movement | type of protozoa, such as Giardia, that moves with flagella. | D: movement. |
Nearly all earthquakes occur where?
Here are the choices:
A. in large cities
B. plate centers
C. in Asia
D. plate boundaries | Nearly all earthquakes occur at plate boundaries, and all types of plate boundaries have earthquakes. | D: plate boundaries. |
Conotoxins released by certain marine snails can bring about paralysis in humans, indicating that this toxin attacks what system?
Here are the choices:
A. cardiovascular
B. cerebral
C. neurological
D. circulatory | Can Snail Venom Be Used as a Pharmacological Painkiller? Marine snails of the genus Conus (Figure 28.25) attack prey with a venomous sting. The toxin released, known as conotoxin, is a peptide with internal disulfide linkages. Conotoxins can bring about paralysis in humans, indicating that this toxin attacks neurological targets. Some conotoxins have been shown to block neuronal ion channels. These findings have led researchers to study conotoxins for possible medical applications. Conotoxins are an exciting area of potential pharmacological development, since these peptides may be possibly modified and used in specific medical conditions to inhibit the activity of specific neurons. For example, these toxins may be used to induce paralysis in muscles in specific health applications, similar to the use of botulinum toxin. Since the entire spectrum of conotoxins, as well as their mechanisms of action, are not completely known, the study of their potential applications is still in its infancy. Most research to date has focused on their use to treat neurological diseases. They have also shown some efficacy in relieving chronic pain, and the pain associated with conditions like sciatica and shingles. The study and use of biotoxins—toxins derived from living organisms—are an excellent example of the application of biological science to modern medicine. | C: neurological. |
What is the second largest planet in the solar system?
Here are the choices:
A. Mars
B. Venus
C. saturn
D. jupiter | Saturn is the second largest planet in the solar system ( Figure below ). Saturn’s mass is about 95 times Earth's mass. The gas giant is 755 times Earth’s volume. Despite its large size, Saturn is the least dense planet in our solar system. Saturn is actually less dense than water. This means that if there were a bathtub big enough, Saturn would float! In Roman mythology, Saturn was the father of Jupiter. Saturn orbits the Sun once about every 30 Earth years. | C: saturn. |
Fruit comes from the ovaries of what types of plants?
Here are the choices:
A. flowering
B. perennial
C. deciduous
D. sprouting | Although flowers and their components are the major innovations of angiosperms, they are not the only ones. Angiosperms also have more efficient vascular tissues. Additionally, in many flowering plants the ovaries ripen into fruits. Fruits are often brightly colored, so animals are likely to see and eat them and disperse their seeds (see Figure below ). | A: flowering. |
Resistors connected end to end are said to be in what?
Here are the choices:
A. series
B. groups
C. lines
D. parallel | Resistors in Series: All resistors are connected end to end. There is only one river, so they all receive the same current. But since there is a voltage drop across each resistor, they may all have different voltages across them – the sum of the voltage drops will equal the total voltage of the circuit. The more resistors in series the more rocks in the river, so the less current that flows. | A: series. |
Molar mass is equal to density multiplied by what?
Here are the choices:
A. molar gravity
B. molar weight
C. molar volume
D. molar energy | Molar mass is equal to density multiplied by molar volume. | C: molar volume. |
What plastid makes and stores other pigments?
Here are the choices:
A. pores
B. pores
C. chromoplasts
D. sporozoans | Chromoplasts are plastids that make and store other pigments. The red pigment that colors the flower petals in Figure above was made by chromoplasts. | C: chromoplasts. |
What effect causes global winds to blow on a diagonal over the earth's surface?
Here are the choices:
A. resonant effect
B. coriolis effect
C. dopler effect
D. centrifugal effect | Global winds occur in belts around the globe. They are caused by unequal heating of Earth’s surface. The Coriolis effect causes global winds to blow on a diagonal over the surface. Unequal heating also causes jet streams high in the troposphere. | B: coriolis effect. |
When members of the same species compete for the same resources, it is called what?
Here are the choices:
A. interspecies competition
B. intraspecific competition
C. natural selection
D. extinction | Intraspecific competition happens when members of the same species compete for the same resources. For example, two trees may grow close together and compete for light. One may out-compete the other by growing taller to get more available light. As members of the same species are usually genetically different, they have different characteristics, and in this example, one tree grows taller than the other. The organism that is better adapted to that environment is better able to survive. The other organism may not survive. In this example, it is the taller tree that is better adapted to the environment. | B: intraspecific competition. |
Antibiotics only target prokaryotic cells - they do not affect fungi, which are not prokaryotic, but instead what?
Here are the choices:
A. chloroplasts
B. plants
C. eukaryotic
D. mammals | Animal and Human Parasites and Pathogens Fungi can affect animals, including humans, in several ways. Fungi attack animals directly by colonizing and destroying tissues. Humans and other animals can be poisoned by eating toxic mushrooms or foods contaminated by fungi. In addition, individuals who display hypersensitivity to molds and spores develop strong and dangerous allergic reactions. Fungal infections are generally very difficult to treat because, unlike bacteria, fungi are eukaryotes. Antibiotics only target prokaryotic cells, whereas compounds that kill fungi also adversely affect the eukaryotic animal host. Many fungal infections ( mycoses) are superficial and termed cutaneous (meaning “skin”) mycoses. They are usually visible on the skin of the animal. Fungi that cause the superficial mycoses of the epidermis, hair, and nails rarely spread to the underlying tissue (Figure 13.26). These fungi are often misnamed “dermatophytes” from the Greek dermis skin and phyte plant, but they are not plants. Dermatophytes are also called “ringworms” because of the red ring that they cause on skin (although the ring is caused by fungi, not a worm). These fungi secrete extracellular enzymes that break down keratin (a protein found in hair, skin, and nails), causing a number of conditions such as athlete’s foot, jock itch, and other cutaneous fungal infections. These conditions are usually treated with over-the-counter topical creams and powders, and are easily cleared. More persistent, superficial mycoses may require prescription oral medications. | C: eukaryotic. |
What do bees carry from one plant to another to facilitate plant growth and development?
Here are the choices:
A. nutrients
B. pollen
C. fungi
D. spores | Bees are beautiful creatures that help plants flourish. They carry pollen from one plant to another to facilitate plant growth and development. But, they can also be troublesome when they sting you. For people who are allergic to bee venom, this can be a serious, life-threatening problem. For the rest of us, it can be a painful experience. When stung by a bee, one first-aid treatment is to apply a paste of baking soda (sodium bicarbonate) to the stung area. This weak base helps with the itching and swelling that accompanies the bee sting. | B: pollen. |
Why is the drift velocity negligible?
Here are the choices:
A. need free charges
B. many free charges
C. less free charges
D. shows free charges | Good conductors have large numbers of free charges in them. In metals, the free charges are free electrons. Figure 20.6 shows how free electrons move through an ordinary conductor. The distance that an individual electron can move between collisions with atoms or other electrons is quite small. The electron paths thus appear nearly random, like the motion of atoms in a gas. But there is an electric field in the conductor that causes the electrons to drift in the direction shown (opposite to the field, since they are negative). The drift velocity v d is the average velocity of the free charges. Drift velocity is quite small, since there are so many free charges. If we have an estimate of the density of free electrons in a conductor, we can calculate the drift velocity for a given current. The larger the density, the lower the velocity required for a given current. | B: many free charges. |
Instruments that measure the angle of the slope of a volcano are called what?
Here are the choices:
A. tilt meters
B. aberration meters
C. angle meters
D. velocity meters | All that magma and gas pushing upward can make the volcano’s slope begin to swell. Ground swelling may change the shape of a volcano or cause rock falls and landslides. Most of the time, the ground tilting is not visible. Scientists detect it by using tiltmeters, which are instruments that measure the angle of the slope of a volcano. | A: tilt meters. |
What is the term for preserved remains or traces of organisms that lived in the past?
Here are the choices:
A. fossils
B. deposits
C. bones
D. remains | Fossils are preserved remains or traces of organisms that lived in the past. Most fossils form in sedimentary rock. Fossils can also be preserved in other ways. Fossilization is rare. It’s very unlikely for any given organism to become a fossil. | A: fossils. |
Birds flying thousands of miles south in the winter, then returning to their homes in spring, is a familiar example of what?
Here are the choices:
A. hibernation
B. migration
C. emigration
D. evacuation | One type of migration that you are probably familiar with is the migration of birds. Maybe you have heard that birds fly south for the winter. In the fall, birds fly thousands of miles to the south where it is warmer. In the spring, they return to their homes. ( Figure below ). | B: migration. |
The hydration of what is what makes many alcohols?
Here are the choices:
A. malts
B. alkenes
C. lipids
D. enzymes | Many alcohols are made by the hydration of alkenes. | B: alkenes. |
What causes oxides to decompose?
Here are the choices:
A. heat
B. precipitation
C. humidity
D. acidity | Found as a pure element in nature; oxides decompose with heating. | A: heat. |
With codominance, both alleles are expressed equally in what?
Here are the choices:
A. heterozygotes
B. homozygotes
C. gametes
D. prokaryotes | With codominance, both alleles are expressed equally in heterozygotes. The red and white flower in Figure below has codominant alleles for red petals and white petals. | A: heterozygotes. |
When hit from behind in a car crash, a passenger can suffer a neck injury called what?
Here are the choices:
A. whiplash
B. inflammation
C. necklash
D. twisted neck | When hit from behind in a car crash, a passenger can suffer a neck injury called whiplash . Explain in terms of inertia how this occurs, and how headrests can prevent the injury. | A: whiplash. |
When a species always migrates, what is this type of migration called?
Here are the choices:
A. mass migration
B. obligate migration
C. emigration
D. genus migration | Although migration is thought of as innate behavior, only some migrating species always migrate (obligate migration). Animals that exhibit facultative migration can choose to migrate or not. Additionally, in some animals, only a portion of the population migrates, whereas the rest does not migrate (incomplete migration). For example, owls that live in the tundra may migrate in years when their food source, small rodents, is relatively scarce, but not migrate during the years when rodents are plentiful. Foraging Foraging is the act of searching for and exploiting food resources. Feeding behaviors that maximize energy gain and minimize energy expenditure are called optimal foraging behaviors, and these are favored by natural section. The painted stork, for example, uses its long beak to search the bottom of a freshwater marshland for crabs and other food (Figure 45.36). | B: obligate migration. |
How are valuable metabolites recovered?
Here are the choices:
A. replication reaction
B. metabolism
C. reabsorption
D. osmosis | Flame Cells of Planaria and Nephridia of Worms As multi-cellular systems evolved to have organ systems that divided the metabolic needs of the body, individual organs evolved to perform the excretory function. Planaria are flatworms that live in fresh water. Their excretory system consists of two tubules connected to a highly branched duct system. The cells in the tubules are called flame cells (or protonephridia) because they have a cluster of cilia that looks like a flickering flame when viewed under the microscope, as illustrated in Figure 41.10a. The cilia propel waste matter down the tubules and out of the body through excretory pores that open on the body surface; cilia also draw water from the interstitial fluid, allowing for filtration. Any valuable metabolites are recovered by reabsorption. Flame cells are found in flatworms, including parasitic tapeworms and free-living planaria. They also maintain the organism’s osmotic balance. | C: reabsorption. |
Structures that have lost their use through evolution are called _______
Here are the choices:
A. residual structures
B. symbiotic structures
C. vestigial structures
D. primordial structures | Some of the most interesting kinds of evidence for evolution are body parts that have lost their use through evolution ( Figure below ). For example, most birds need their wings to fly. But the wings of an ostrich have lost their original use. Structures that have lost their use through evolution are called vestigial structures . They provide evidence for evolution because they suggest that an organism changed from using the structure to not using the structure, or using it for a different purpose. | C: vestigial structures. |
What does continental crust grade into at continental margins?
Here are the choices:
A. remnants crust
B. ocean floor
C. storm crust
D. oceanic crust | Think of a continent, like North America. Surrounding the continent are continental margins . Continental crust grades into oceanic crust at continental margins. Continental margins are under water. Almost all of North America sits on the North American Plate ( Figure below ). Both sides of the continent have continental margins, but each is very different. One continental margin of North America is an active margin. The other is a passive margin. Can you guess which is which?. | D: oceanic crust. |
What body system consists of organs that break down food, absorb nutrients, and eliminate waste?
Here are the choices:
A. skeletal system
B. hormonal system
C. lymphatic system
D. digestive system | The digestive system consists of organs that break down food, absorb nutrients, and eliminate waste. | D: digestive system. |
Some samples of matter appear to have properties of solids, liquids, and/or gases at the same time. this can occur when the sample is composed of many what?
Here are the choices:
A. small pieces
B. turn pieces
C. few pieces
D. large pieces | Some samples of matter appear to have properties of solids, liquids, and/or gases at the same time. This can occur when the sample is composed of many small pieces. For example, we can pour sand as if it were a liquid because it is composed of many small grains of solid sand. Matter can also have properties of more than one state when it is a mixture, such as with clouds. Clouds appear to behave somewhat like gases, but they are actually mixtures of air (gas) and tiny particles of water (liquid or solid). The mass of an object is a measure of the amount of matter in it. One way to measure an object’s mass is to measure the force it takes to accelerate the object. It takes much more force to accelerate a car than a bicycle because the car has much more mass. A more common way to determine the mass of an object is to use a balance to compare its mass with a standard mass. Although weight is related to mass, it is not the same thing. Weight refers to the force that gravity exerts on an object. This force is directly proportional to the mass of the object. The weight of an object changes as the force of gravity changes, but its mass does not. An astronaut’s mass does not change just because she goes to the moon. But her weight on the moon is only one-sixth her earth-bound weight because the moon’s gravity is only one-sixth that of the earth’s. She may feel “weightless” during her trip when she experiences negligible external forces (gravitational or any other), although she is, of course, never “massless. ” The law of conservation of matter summarizes many scientific observations about matter: It states that there is no detectable change in the total quantity of matter present when matter converts from one type to another (a chemical change) or changes among solid, liquid, or gaseous states (a physical change). Brewing beer and the operation of batteries provide examples of the conservation of matter (Figure 1.8). During the brewing of beer, the ingredients (water, yeast, grains, malt, hops, and sugar) are converted into beer (water, alcohol, carbonation, and flavoring substances) with no actual loss of substance. This is most clearly seen during the bottling process, when glucose turns. | A: small pieces. |
Stimuli in the brain, stomach, and small intestine activate or inhibit production of what secretion?
Here are the choices:
A. digestive juice
B. sweat
C. metabolic juice
D. gastric juice | Gastric Secretion The secretion of gastric juice is controlled by both nerves and hormones. Stimuli in the brain, stomach, and small intestine activate or inhibit gastric juice production. This is why the three phases of gastric secretion are called the cephalic, gastric, and intestinal phases (Figure 23.17). However, once gastric secretion begins, all three phases can occur simultaneously. | D: gastric juice. |
What is the term for a symbiotic relationship in which one species benefits while the other species is not affected?
Here are the choices:
A. parasitism
B. commensalism
C. pollenation
D. mutualism | Commensalism is a symbiotic relationship in which one species benefits while the other species is not affected. An example is the relationship between birds called cattle egrets and cattle (see Figure below ). Cattle egrets feed on insects. They follow cattle herds around to take advantage of the insects stirred up by the feet of the cattle. The egrets get ready access to food from the relationship, whereas the cattle are not affected. | B: commensalism. |
What does the a1c test measure over the past two to three months?
Here are the choices:
A. RBC levels
B. albumin levels
C. blood-glucose levels
D. cholesterol levels | Endocrinologist An endocrinologist is a medical doctor who specializes in treating endocrine disorders. An endocrine surgeon specializes in the surgical treatment of endocrine diseases and glands. Some of the diseases that are managed by endocrinologists include disorders of the pancreas (diabetes mellitus), disorders of the pituitary (gigantism, acromegaly, and pituitary dwarfism), disorders of the thyroid gland (goiter and Graves’ disease), and disorders of the adrenal glands (Cushing’s disease and Addison’s disease). Endocrinologists are required to assess patients and diagnose endocrine disorders through extensive use of laboratory tests. Many endocrine diseases are diagnosed using tests that stimulate or suppress endocrine organ functioning. Blood samples are then drawn to determine the effect of stimulating or suppressing an endocrine organ on the production of hormones. For example, to diagnose diabetes mellitus, patients are required to fast for 12 to 24 hours. They are then given a sugary drink, which stimulates the pancreas to produce insulin to decrease blood-glucose levels. A blood sample is taken one to two hours after the sugar drink is consumed. If the pancreas is functioning properly, the blood-glucose level will be within a normal range. Another example is the A1C test, which can be performed during blood screening. The A1C test measures average blood-glucose levels over the past two to three months. The A1C test is an indicator of how well blood glucose is being managed over a long time. Once a disease such as diabetes has been diagnosed, endocrinologists can prescribe lifestyle changes and medications to treat the disease. Some cases of diabetes mellitus can be managed by exercise, weight loss, and a healthy diet; in other cases, medications may be required to enhance insulin’s production or effect. If the disease cannot be controlled by these means, the endocrinologist may prescribe insulin injections. In addition to clinical practice, endocrinologists may also be involved in primary research and development activities. For example, ongoing islet transplant research is investigating how healthy pancreas islet cells may be transplanted into diabetic patients. Successful islet transplants may allow patients to stop taking insulin injections. | C: blood-glucose levels. |
What is the term for liquid waste formed by kidneys?
Here are the choices:
A. sperm
B. urine
C. blood
D. feces | Urine is a liquid waste formed by the kidneys as they filter the blood. If you are getting plenty of fluids, your urine should be almost clear. But you might have noticed that sometimes your urine is darker than usual. Do you know why this happens? Sometimes your body is low on water and trying to reduce the amount of water lost in urine. Therefore, your urine gets darker than usual. Your body is striving to maintain homeostasis through the process of excretion. | B: urine. |
Why does metal conduct heat and electricity so well?
Here are the choices:
A. free flowing electrons
B. insulation
C. electromagnetism
D. free flowing photons | The metallic bonding model explains the physical properties of metals. Metals conduct electricity and heat very well because of their free-flowing electrons. As electrons enter one end of a piece of metal, an equal number of electrons flow outward from the other end. When light is shone on to the surface of a metal, its electrons absorb small amounts of energy and become excited into one of its many empty orbitals. The electrons immediately fall back down to lower energy levels and emit light. This process is responsible for the high luster of metals. | A: free flowing electrons. |
Liverworts are small plants that grow close to what?
Here are the choices:
A. tree tops
B. beaches
C. ground
D. houses | Liverworts are small plants that grow close to the ground. | C: ground. |
What do atoms make by rearranging their chemical bonds in a reactant?
Here are the choices:
A. compounds
B. minerals
C. solutions
D. products | When a chemical reaction occurs, the atoms in the reactants rearrange their chemical bonds to make products. The new arrangement of bonds does not have the same total energy as the bonds in the reactants. Therefore, when chemical reactions occur, there will always be an accompanying energy change. In some reactions, the energy of the products is lower than the energy of the reactants. Thus, in the course of the reaction, the substances lose energy to the surrounding environment. Such reactions are exothermic and can be represented by an energylevel diagram like the one in http://catalog. flatworldknowledge. com/bookhub/reader/2547 gob-ch07_s04_f01. In most cases, the energy is given off as heat (although a few reactions give off energy as light). Figure 7.3 Exothermic Reactions. | D: products. |
Spindle fibers pull what apart in anaphase i?
Here are the choices:
A. risk chromosomes
B. True Chromosomes
C. linked chromosomes
D. known chromosomes | In anaphase I, the spindle fibers pull the linked chromosomes apart. The sister chromatids remain tightly bound together at the centromere. It is the chiasma connections that are broken in anaphase I as the fibers attached to the fused kinetochores pull the homologous chromosomes apart (Figure 7.5). In telophase I, the separated chromosomes arrive at opposite poles. The remainder of the typical telophase events may or may not occur depending on the species. In some organisms, the chromosomes decondense and nuclear envelopes form around the chromatids in telophase I. Cytokinesis, the physical separation of the cytoplasmic components into two daughter cells, occurs without reformation of the nuclei in other organisms. In nearly all species, cytokinesis separates the cell contents by either a cleavage furrow (in animals and some fungi), or a cell plate that will ultimately lead to formation of cell walls that separate the two daughter cells (in plants). At each pole, there is just one member of each pair of the homologous chromosomes, so only one full set of the chromosomes is present. This is why the cells are considered haploid—there is only one chromosome set, even though there are duplicate copies of the set because each homolog still consists of two sister chromatids that are still attached to each other. However, although the sister chromatids were once duplicates of the same chromosome, they are no longer identical at this stage because of crossovers. | C: linked chromosomes. |
What type of mutations cannot be passed on to offspring?
Here are the choices:
A. instructional mutations
B. symbiotic mutations
C. somatic mutations
D. functional mutations | Somatic mutations occur in other cells of the body. These mutations may have little effect on the organism because they are confined to just one cell and its daughter cells. Somatic mutations cannot be passed on to offspring. | C: somatic mutations. |
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