Which statement is best supported by the phenotypes of these offspring?
A The F₁ generation is composed only of males.
B Two of the offspring in the F₁ generation will not be able to reproduce.
C The F₁ generation is the result of a dihybrid cross.
D Two of the offspring in the F₁ generation will experience a spontaneous mutation.

C

The 1918 influenza epidemic killed between 50 million and 100 million people worldwide. This epidemic happened near the end of World War I. More people died from the influenza epidemic than were killed in the war. Which of the following explains why this virus was so deadly worldwide?
F Infected soldiers returning from the war spread the virus when they coughed.
G Food was scarce because of the war, so people were undernourished, and their immune systems were weakened.
H Medical personnel often became ill as a result of exposure to airborne virus particles.
J All of the above

J

Based on this model, how much of the energy was provided to secondary consumers?
A 53,460 J
B 5,400 J
C 540 J
D 54 J

B

The survival of a species depends on its ability to adapt to changes in the environment. A species must be capable of surviving and reproducing despite changes to food sources, climate, or threats from predators. Which statement correctly describes a way that mutations increase the likelihood that a species will survive in a changing environment?
F Mutations are a source of variation in the species.
G Mutations are the cause of disease in the species.
H Mutations are not harmful when they occur in somatic cells of the species.
J Mutations are always passed on to subsequent generations of the species.

F

Which statement explains the effect of an inhibitor on an enzyme?
A A substrate will be able to bond with the enzyme.
B The enzyme will likely be attacked by immune cells.
C The enzyme will be unable to produce more enzymes.
D A substrate will be unable to attach to the enzyme.

D

Four different nucleotides are used as building blocks of DNA. Which of the following can be used to distinguish one nucleotide from another?
F The nitrogenous base
G The shape of the deoxyribose sugar
H The length of the phosphate group
J The type of fatty acid

F

Why does the ability to lay 1,000 to 5,000 eggs increase the fitness of the species L. clamitans clamitans?
A It increases opportunities for offspring to compete for limited resources.
B It increases the probability that some offspring will survive long enough to reproduce.
C It increases the probability that moving water will promote gene flow from one population to another.
D It increases the chance of the recombination of alleles, leading to genetic drift in the population.

B

An environmental change that removed which of these organisms from the ecosystem would cause the most instability in the ecosystem?
F Auklets
G Foxes
H Salmon
J Zooplankton

J

During the final stages of human gestation, receptors for the hormone oxytocin increase on the smooth muscle cells of the uterus. The release of oxytocin during labor stimulates the smooth muscle tissue in the wall of the uterus. The vigorous contraction of the uterine smooth muscle helps push the baby through the birth canal so that delivery can occur. This process involves the interaction of which organ systems?
A Endocrine and muscular only
B Endocrine and reproductive only
C Endocrine, muscular, and reproductive
D Endocrine, reproductive, and excretory

C

In the early 1900s a scientist hypothesized a link between DNA and the production of proteins in the cytoplasm. However, the fact that DNA could not be found outside the nucleus led scientists to believe that another substance was also involved in the synthesis of protein in the cytoplasm. In the 1940s scientists performed an experiment that ultimately identified the site of protein synthesis. They also identified the molecule responsible for transporting information from the nucleus to the site of protein synthesis. What was this newly identified molecule?
F A gene
G mRNA
H ATP
J Thymine

G

During meiosis, homologous chromosomes exchange genetic material. This exchange of genetic material —
A increases the genetic variation
B reduces the diploid number to the haploid number
C increases the haploid number to the diploid number
D reduces the probability of mutations

A

As a fertilized egg divides, the cells differentiate because they —
F contain a lipid bilayer
G can clump together
H metabolize sugars rapidly
J have specific genes activated

J

What is the most likely reason the population of these butterflies has been declining?
A The number of bird species evolving to prey on butterflies has increased.
B The butterflies are evolving to tolerate cold weather in the northern United States and southern Canada.
C The increase in yearly temperatures has warmed the northern habitats.
D The number of milkweed plants along the butterflies’ migratory route has decreased.

D

Bactrian camels, dromedaries, llamas, and alpacas are all members of the same taxonomic family, Camelidae. Members of this family all have two toes, no hooves, true canine teeth, and a split upper lip. The family Camelidae originated in North America. The physical features of animals in this family and the family’s geographical origin provide evidence that all these animals —
F live in the same type of ecosystem
G have slowly evolved to become herbivores
H have a common ancestor
J exchanged DNA at some point in the past

H

Which statement best describes the relationship between the products of photosynthesis and the reactants in cellular respiration?
A The products of photosynthesis serve as the reactants in cellular respiration to provide chemical energy.
B The products of photosynthesis combine with the reactants in cellular respiration to remove ATP from cells.
C The products of photosynthesis inhibit the reactants in cellular respiration in the presence of light.
D The products of photosynthesis change the structure of the reactants in cellular respiration in the presence of light.

A

Why does this type of bacteria-filled supplement benefit human health instead of causing illness?
F Stomach acids and digestive enzymes kill the bacteria in this type of supplement, protecting the person against future infections by live organisms.
G The human digestive system contains billions of beneficial bacteria that enhance digestion and nutrient absorption, synthesize vitamins, and help limit the growth of harmful bacteria.
H These species of bacteria remove all the other species of microorganisms living in the human digestive system and ensure that no microorganisms survive to contaminate the body.
J These bacteria are able to deactivate viruses that may inhabit the human digestive system and are used to protect against further viral infections.

G

Which process and product are represented in Diagram 2?
A Process: transcription; product: mRNA
B Process: translation; product: protein
C Process: replication; product: tRNA
D Process: recombination; product: polymerase

A

While visiting a national park, a student encounters an unfamiliar organism in a damp area near a body of water. The student notes that the organism is about 10 cm long, has four legs, and has a tail. The organism is black with small white spots on its smooth, moist skin. It also appears to have an internal skeletal system. To which class does the organism most likely belong?
F Reptilia
G Amphibia
H Mammalia
J Insecta

G

During ecological succession, how does the growth of young hardwoods affect the organisms living in an ecosystem?
A Grasses and low shrubs are unable to obtain the amount of light they need to survive, so there are small numbers of them.
B The trees provide shelter and food for a variety of mammals, insects, and birds.
C In autumn, falling leaves provide a source of energy for decomposers such as fungi.
D All of the above

D

Human bone, muscle, and nerve cells all contain the same number of chromosomes with the same complement of genes. What enables these cells to perform specialized activities?
F The ability of some cells to remove unnecessary DNA sequences
G The regulation of gene expression within each cell type
H The mutation of genes within each cell type
J The use of different methods of cell division

G

D

Cytokinins are a class of plant hormones that help regulate growth by promoting cell division. Cytokinins are produced mainly in meristematic tissue, where most plant growth occurs. Which system carries cytokinins produced in the roots to the rest of the plant?
F Vascular system
G Dermal system
H Reproductive system
J None of these

F

The adaptation that allows some of these animals to run fast would be an example of natural selection if it helps them —
A survive and undergo mutations in their DNA
B lower the mortality rates of the population
C produce offspring that run at average speeds
D reproduce and increase the frequency of their genes in the population

D

Which cell is in the phase of mitosis that the student is searching for?
F Cell 1
G Cell 2
H Cell 3
J Cell 4

G

Which of these best explains what is happening to the quiver tree population in southern Africa?

A Individual quiver trees are unable to adjust to the rising temperatures, and only those in cooler parts of the range will survive.
B The quiver tree species is unable to survive rising temperatures throughout its range. The species is likely to undergo rapid extinction.
C Individual quiver trees can quickly adapt to rising temperatures. Individual trees will change their method of seed dispersal in cooler parts of the range.
D The quiver tree species will survive by producing offspring suited for warmer temperature

A

Scientists studying illnesses caused by chemically contaminated food conduct research to minimize the effects of these diseases on society. These chemicals harm the body through interactions between the digestive system and the immune system. Scientists conducting this research are likely to describe which of these interactions between the digestive and immune systems?
F Chemicals enter the immune system through a break in the skin. The chemical
contamination is then passed to the digestive system by the circulatory system.
G The immune system transforms the chemicals in the contaminated foods into harmless chemicals. These harmless chemicals are then broken down by the digestive system.
H When contaminated foods are eaten, the immune system prevents the chemicals from entering the digestive system.
J Chemicals enter the digestive system through contaminated foods. Once in the body, the chemical contaminants impair the body’s ability to fight off infectious diseases.

J

Nitrogenous bases are located on both strands of the DNA double helix. What is the significance of the nitrogenous bases?
A The number of adenines and cytosines determines the type of RNA that will be produced.
B The order of nitrogenous bases determines the order of amino acids in the proteins synthesized.
C The amount of thymine and guanine in the DNA molecules determines the length of the genes.
D The type of hydrogen bonding between the nitrogenous bases determines which amino acid will be added to the peptide chain.

B

Which two processes does this diagram most directly model?
F Energy conversions and synthesis of new molecules
G Synthesis of new molecules and homeostasis
H Transport of molecules and energy conversions
J Homeostasis and transport of molecules

J

In the early 1980s scientists were able to produce two biomolecules by splicing a human gene into the bacterium E. coli to make recombinant human insulin and growth hormone. Which statement best explains why this experiment was successful?
A Human cells are eukaryotic, and E. coli cells are prokaryotic.
B All living organisms share the same genome.
C The genes for all organisms are composed of the same building blocks.
D The human body contains many types of bacteria, including E. coli.

C

Kidneys are part of the excretory system in a human body. They purify the impure blood and send it back to the rest of the body. Which system is mainly responsible for the transport of plasma to the kidneys?
F Respiratory system
G Circulatory system
H Muscular system
J Nervous system

G

Which organisms are both secondary and tertiary consumers in this food web?
A Chemosynthetic bacteria and amphipods
B Zooplankton and mussels
C Ratfish and octopuses
D Galatheid crabs and zoarcid fish

C

F

B

Cells pass through a Gcheckpoint before entering mitosis. Ideally, if DNA damage is 2 detected, the cells do not enter mitosis until the damage is repaired. Why is DNA damage repaired before cells enter mitosis?
F So that another round of DNA synthesis does not have to take place
G So that the chromosomes can align at the metaphase plate during mitosis
H So that the cytoplasm can be divided equally between the two daughter cells
J So that healthy daughter cells are produced, allowing the organism to continue

J

Which mutation will cause translation to stop?
A Mutations 1 and 3 only
B Mutation 1 only
C Mutation 2 only
D Mutations 1, 2, and 3

B

In what way are the bacteriophage and E. coli alike?
F They contain antibodies.
G They reproduce by mitosis.
H They have identical genomes.
J They lack membrane-bound organelles.

J

Based on the key, which of these best describes the leaves and cones of the longleaf pine?
A Needle-like straight leaves that are mostly over 25 cm long and found in clusters of three; no thorns on cones
B Flattened and scale-like leaves that are mostly over 25 cm long; soft and leathery cones
C Needle-like straight leaves with a length of 25 cm that are mostly found in clusters of five; thorny cones
D Leaves with a length of 25 cm that are found in clusters of more than five; no thorns on cones

A

People who have Alzheimer’s disease experience an increasing loss of brain function and cognition over time. Alzheimer’s is characterized by a buildup of abnormal protein fragments that damage brain cells. Recently scientists have discovered an enzyme, BACE2, that decreases these abnormal protein fragments in the brain of a person with Alzheimer’s disease. Which statement explains how BACE2 most likely works?
F BACE2 breaks down into smaller pieces that react with the abnormal protein fragments, forming more complex molecules.
G BACE2 speeds up the reaction that breaks down the abnormal protein fragments.
H BACE2 molecules link several abnormal protein fragments together, forming a complete protein.
J BACE2 is a reactant that combines with the abnormal protein fragments.

G

In all three complex carbohydrates, the subunits of glucose are bonded together differently. Because they have different structures, they most likely —
A contain different chemical elements
B form different proteins
C carry different nucleotides
D perform different functions

D

In 2010, scientists excavated a skull fossil that provides evidence of a newly discovered species of big cat. Based on the evidence, scientists hypothesize that big cats branched off from smaller wild cats about 6 million years ago. Which of these resources did the scientists most likely rely on to form their hypothesis?
F A food web showing feeding relationships of organisms where the fossil skull was found
G Population and migration data for small wild cats living in the ecosystem where the skull was found
H The fossil record and DNA comparisons of big cats and small cats
J The historical record of interactions between different species of big cats

H

Which of the following is most likely to cause the greatest disruption to an ecosystem?
A Emptying an aquarium containing non-native species into a local waterway
B Cutting down a small cedar tree to make holiday decorations
C Cleaning the windshield of a car with an alcohol-based glass cleaner
D Mowing the lawn in a city park

A

H

Which statement best describes the differences in species diversity between an ecosystem beginning the process of primary succession and one beginning the process of secondary succession?
A Species diversity is much greater in the ecosystem undergoing primary succession because that ecosystem is experiencing a longer period with a lack of competition for space.
B No differences in species diversity exist because both ecosystems initially lack living organisms.
C Species diversity is much greater in the ecosystem undergoing primary succession because the lack of soil provides a greater area for organisms to claim niches.
D Species diversity is greater in the ecosystem undergoing secondary succession because the soil already contains seeds and spores of various species.

D

In which of these situations would PCR be most useful?
F When only a small amount of DNA is available, such as at a crime scene
G When the DNA of identical twins is being mapped
H When the genome of a population is being analyzed for preventable diseases
J When the blood type of a DNA donor is known

F

Which statement explains the pattern in the graph?
A Body temperature varies in a predictable pattern during the day.
B Body temperature is controlled by an internal feedback mechanism.
C Vasodilation and vasoconstriction are dependent on the time of day.
D Vasodilation and vasoconstriction trigger an immediate increase in body temperature.

B

Chickens can have different types of feathers. Frizzled feathers curl toward a chicken’s head. Assume that feather type is determined by a single gene and that the allele for frizzled feathers is dominant over the allele for straight feathers. In a cross between two chickens with straight feathers, what percentage of the offspring can be expected to have frizzled feathers?
F 0%
G 25%
H 50%
J 100%

F

Which student made observations of a community of organisms?
A Student 1
B Student 2
C Student 3
D Student 4

B

Atmospheric nitrogen has to be combined with other elements, or fixed, in order to be used by plants. Lightning is one way that nitrogen is fixed. When lightning occurs, the extreme heat breaks the bonds in nitrogen molecules, allowing nitrogen to combine with oxygen and form nitrogen oxides. In what way is most of the nitrogen fixed by lightning made available for use by plants?
F It is moved by the wind toward dry areas.
G It is incorporated into the exoskeletons of flying insects that eat plants.
H It is inhaled and exhaled by birds roosting in trees during rainstorms.
J It is carried by rain to the soil.

J

Based on this information, what functions do the specialized leaves of sundews perform?
A Provide water to the plant and perform photosynthesis
B Respond to stimuli and anchor the plant
C Provide nutrients to the plant and respond to stimuli
D Release pollen to insects and perform photosynthesis

C

Oncogenes are mutated forms of genes. Oncogenes can transform a cell into a tumor cell. Some tumor cells are benign, while others are malignant. How does the presence of an oncogene lead to the formation of a tumor?
F ATP production is inhibited.
G Cell division is unregulated.
H Somatic cell growth is inhibited.
J Antibody activity is unregulated.

G

Scientists around the world use a standardized taxonomic system. Why would scientists want to use a taxonomic system that is standardized?
A In order to avoid confusion with the identification of organisms
B Because Linnaeus established the system
C So that Latin names can be applied for a practical purpose
D In order to place organisms in different groups

A

H

A student performed an investigation in which two ivy plants were planted in two separate containers. One of the containers had earthworms mixed in with the soil, and the other container had soil and no earthworms. The plants were given the same amount of water and exposed to the same amount of sunlight. The student observed that after several weeks of growth, the plant exposed to earthworms appeared to be healthier and exhibited more growth. To conclude that the relationship between the plant and the earthworm is an example of mutualism, the student must perform follow-up investigations that do which of the following?
A Determine whether the earthworms damage the soil in any way
B Determine whether the earthworms benefit from being with the plant
C Determine whether the water given to the plant is unpolluted
D Determine whether the other plant in the investigation suffers as a result of not being exposed to earthworms

B

Based on this information, how has adaptation allowed marine gastropods to be successful without a shell?
F They find enough food as they move through the marine environment.
G They blend in with their environment to hide from their predators.
H They are not attacked by most predators and are able to reproduce successfully.
J They have bright colors that attract a mate.

H

A single-celled organism can be classified as a prokaryote based on the absence of —
A a cell membrane
B ribosomes
C chromosomes
D a nucleus

D

Which statement describes the mutation in the diagram?
F A silent mutation results in the insertion of a different amino acid.
G A substitution occurs with the adenine base.
H A deletion of a cytosine base occurs.
J A base is inserted into one strand of the DNA.

J

The relationship between the remora and the shark is an example of —
A predation
B parasitism
C commensalism
D competition

C

Invasive plant species affect the interactions of living and nonliving components of an ecosystem, so the removal of invasive plants is often necessary. The goal of most plant-control methods is to disrupt or inhibit the function of different plant systems. For example, insects can be used to chew through roots in order to reduce a plant’s ability to absorb water. Which of these functions would be most immediately affected by a reduction in water uptake by roots?
F Disease resistance
G Seed dispersal
H Sunlight absorption
J Photosynthesis

J

Which of these will most likely happen if the plateau pikas are completely removed from the Tibetan plateau grasslands?
A The ecosystem will become unstable because predators will have fewer prey, the birds will have fewer nesting sites, and the area downriver will become vulnerable to flooding without the burrows to aerate the soil and provide drainage for monsoon rains.
B The ecosystem will become more stable because the pika will be replaced by other species of small mammals that can fill the niche, bird species will adapt to nesting aboveground, and the soils will become compacted without the burrows.
C The ecosystem will become unstable because the predators will migrate to nearby ecosystems, the birds will nest in nearby trees, and the soils will be aerated by other small mammals.
D The ecosystem will become more stable because the pika will no longer be there to eat the grasses, the birds will migrate to other ecosystems during nesting season, and the soils will be able to absorb more of the monsoon rains without the pika burrows.

A

F

This part of the cell cycle is best described as the process that —
A duplicates the DNA
B completes cell division
C maintains genetic homeostasis
D synthesizes new molecules

B

Which statement about enzyme activity is best supported by this graph?
F An enzyme must be composed of multiple polypeptides, or subunits, to be active.
G An enzyme’s rate of activity increases with time until it becomes inactive.
H An enzyme functions best under specific temperature conditions.
J An enzyme works equally well in bacteria that are adapted to high temperatures and in eukaryotic cells such as human cells.

H

The human immunodeficiency virus (HIV) often infects and destroys CD4 T cells. These CD4 T cells are one of many kinds of white blood cells that are an important part of the immune system. The most common danger related to the destruction of CD4 T cells is —
A an increase in the risk of high blood pressure
B an increase in the threat of diseases caused by microorganisms and viruses
C a decrease in the flow of blood to vital organs
D a decrease in the amount of oxygen being transported to tissues

B

Common baboons live on the savanna in breeding groups called troops. While females tend to stay with the troop, younger or less dominant males may leave to join a neighboring troop. Which of these is a likely outcome of movement by young males?
F Gene flow occurs between populations.
G Allele frequencies suddenly change.
H Relative genotypic frequencies reach a constant state.
J Intermediate phenotypes increase in the species.

F

An estuary collects sediments from the ocean and rivers that feed into it. The sediments swirl around and then settle to form a mudflat. Eel grass is then established on the mudflat. The ecosystem changes over time and ultimately develops into a salt marsh that contains mangrove trees.
Which of the following is likely NOT involved in this example of ecological succession?
A The rotting remains of plants add to the fertility of the soil.
B The soil becomes so fertile that eel grass is replaced by other plant species.
C The roots from plants help stabilize the sediment, keeping it in place.
D The concentration of salt becomes so high that all plant life is destroyed.

D

Differences in traits such as hair texture are determined by differences in —
F the location of sugar groups in DNA
G the sequence of nucleotides in DNA
H the number of nitrogenous bases in DNA
J the molecules attached to the phosphate in DNA

G

A

Which statement is best supported by these data?
F Competition for food and shelter among reptile species was very low during the Triassic period.
G A great extinction occurred during the Jurassic period.
H Environmental conditions for speciation were most favorable for reptiles during the Permian period.
J Reptiles adapted to a terrestrial environment during the Cretaceous period.

G

Which body systems are directly responsible for regulating these nodes and protecting the body from harmful materials in tissue fluid?
A Immune and lymphatic systems
B Digestive and nervous systems
C Endocrine and digestive systems
D Circulatory and nervous systems

A

An increase in the amount of carbon dioxide in the atmosphere can cause atmospheric temperatures to increase. Which statement explains how this could affect the ocean as a carbon sink?
F Less atmospheric carbon dioxide would be available to phytoplankton.
G Dissolved carbon dioxide gas in the ocean would increase because surface winds would cause a deeper circulation pattern, making more room for the gas.
H Less carbon dioxide gas would be contained in the ocean because increasing precipitation would dilute the carbon entering the ocean.
J Less carbon dioxide would be dissolved in the ocean because increasing atmospheric temperatures would cause ocean temperatures to increase.

J

Which molecule synthesized by plants is a major source of energy for cellular processes in both plants and animals?
A Wax
B Nucleic acid
C Glucose
D Chlorophyll

C

The results provide evidence that —
F similar nucleotides are present in both fruit-fly and frog DNA
G fruit flies and frogs can be made to develop some of the same physical traits
H heat can cause mutations in the DNA sequences of organisms
J the replication of genetic material can occur at any temperature

F

From a single fertilized ovum undergoing a series of rapid cell divisions, a human infant develops. The embryonic cells become specialized for a variety of functions. Which of these statements best describes how different cell types develop?
A Each cell type contains only the active parts of the DNA needed for that cell type.
B Each cell type has only one chromosome containing the DNA needed for that cell type.
C Each cell has an identical copy of DNA with enzymes controlling the expression of specific genes, leading to a variety of cells.
D Each cell has multiple copies of DNA that are affected in different ways by the
environment to change the function of the cell at regular intervals.

C

This feed back loop is likely to be activated when—
F the body experiences dehydration
G blood glucose levels are stable
H body temperature drops
J the urinary tract is infected

F

In the 1940s, the scientist J. B. S. Haldane linked many human red blood cell disorders with the tropical regions where malaria occurs. Haldane hypothesized that the widespread presence of these red blood cell disorders as well as traits that protect individuals from malaria were the result of natural selection. Haldane’s hypothesis was later confirmed by the research of A. C. Allison.
The resistance to malaria carried by individuals in areas where malaria is widespread is the result of —
A a vaccine against malaria
B the individuals’ genetic composition
C antibiotic medications
D the individuals’ behavior in avoiding those with the infection

B

Which of the following represents evidence that could be used to support the claims about this product?
F Complex carbohydrates are found in vegetables and grains, which are good sources of fiber, vitamins, antioxidants, and minerals. Vegetables and grains are known to reduce the risk of heart disease.
G Some nutritional supplements provide vitamins and minerals that are missing from a person’s diet. These types of nutritional supplements contain important nutrients that reduce the risk of malnutrition.
H Consuming enzymes specific for carbohydrate digestion helps the body digest complex carbohydrates more quickly in the stomach and small intestine.
J Some nutritional supplements add beneficial bacteria to a person’s diet. These bacteria populate the stomach and prevent carbohydrate digestion.

H

Which conclusion about the relatedness of the lizards do these data support?
A G. atlantica and G. stehlini are the least closely related.
B G. simonyi and G. bravoana are the most closely related.
C G. galloti eisentrauti and G. galloti palmae are the most closely related.
D G. galloti eisentrauti and G. galloti galloti are the least closely related.

B

Based on the energy flow between trophic levels in an energy pyramid, how much energy would be expected to be found at the secondary consumer level in this pyramid?
F 100 joules
G 500 joules
H 1,000 joules
J 50 joules

F

Which tree does the unknown leaf come from?
A Ungnadia speciosa
B Sophora secundiflora
C Salix nigra
D Quercus laceyi

D

The donor of which sample is most closely related to the donor of the unknown sample?
F Sample 1
G Sample 2
H Sample 3
J Sample 4

H

Based on this information, the student can conclude that boron is absorbed by plant roots from soil and then —
A transported to reproductive tissues by the plant’s shoot system
B stored in plant stems until the flowers are pollinated
C concentrated in the roots until the plant’s reproductive tissues mature
D transported by the phloem to the stomata in leaves, where it attracts pollinators

A

The surface of the stomach is lined with epithelial cells called surface mucous cells. These cells produce a thick mucus that coats the epithelium on the inside surface of the stomach. What is the purpose of the mucous coating?
F It allows the epithelium to aid in the process of digestion.
G It causes the epithelium to expand as food enters the stomach.
H It protects the epithelium from the acid content of the stomach.
J It traps nutrients inside the epithelium as food passes through the stomach.

H

D

Which statement correctly addresses the validity of the claim?
F The claim is valid because many studies and experiments have shown that bacteria disrupt homeostasis.
G The claim is invalid because there are many types of bacteria that help organisms maintain homeostasis.
H The claim is invalid because only microorganisms such as viruses disrupt the health of organisms.
J The claim is valid because bacteria cause disease.

G

Which of the following is an example of the endocrine system directly interacting with the nervous system?
A The vertebrae protect the spinal cord from injury.
B Hormones provide feedback that affects neural processing.
C Sensory receptors in bones send signals about body position to the brain.
D The brain sends signals that control the speed at which food moves through the intestines.

B

Roads are often built through forests for industrial purposes or as land is developed for residential and commercial needs. How would road construction through a forest most likely affect the ecosystem?
F Non-native species would replace native species.
G The number of primary consumers would increase.
H The natural succession of vegetation would change.
J All producers would be eliminated from the community.

H

People who have leukemia, a cancer that affects white blood cells, are often given Cytarabine. This drug inhibits the synthesis of DNA. Which phase of the cell cycle is most affected by Cytarabine?
A G1phase
B S phase
C G2 phase
D M phase

B

Which theory is represented in this diagram?
F The theory that all living organisms are made of cells
G The theory that all living organisms share the same basic genetic components
H The theory that organisms function best when their internal conditions are maintained within narrow limits
J The theory that complex cells evolved after primitive cells engulfed bacterial cells that continued functioning

J

Recent studies in bone research indicate that using ultrasound on a broken bone can decrease the healing time by 25%. Which of these are the most basic levels of organization involved when a bone heals?
A Cells and tissue
B Cells and organ system
C Organ system and organism
D Tissue and organ system

A

Which of these is the direct result of an error in the transcription of a DNA nucleotide?
F The nuclear membrane is ruptured.
G Amino acids do not bond to tRNA.
H A codon sequence is incorrect.
J Transportation of mRNA does not occur.

H

D

Which statement best explains why the grass tips of the experimental group bent toward the light?
F Water evaporated faster on the side of the plant having full light.
G Light sensors in the grass tips stimulated a hormone in the shoot system.
H The xylem in the root system absorbed more nutrients from the shaded side.
J The side facing the light has a greater chance of absorbing carbon dioxide from the atmosphere.

G

C

What conditions cause the contractile vacuole to fill with water?
F The concentration of water is greater outside the cell than inside the cell.
G The temperature of water in the vacuole is higher than the temperature of its
environment.
H The concentration of water inside the cell is the same as the concentration outside the cell.
J The temperature of water in the vacuole is lower than the temperature of its environment.

F

The rocky material left behind by a retreating glacier forms what is called a moraine. When primary succession occurs on a moraine, which life-forms will help create the soil by breaking down bare rock?
A Insects
B Lichens
C Grasses
D Deciduous trees

B

Taxonomic classification is important to marine biologists because it provides a way to —
F prove that marine evolution occurs
G discover and name every marine organism on Earth
H designate Latin as the universal language of marine biology
J identify marine organisms and find evolutionary relationships between them

J

How are ferritin and glycogen similar in their primary functions for an organism?
A Both store materials needed by the organism.
B Both store energy used by the organism.
C Both support the structure of the organism.
D Both store information for the organism.

A

What is the purpose of this process?
F To replicate the DNA of an organism before cell division
G To assemble nucleotides in an mRNA chain along a DNA template
H To synthesize amino acids used to unzip strands of DNA and copy the genetic code
J To translate the genetic code into a specific sequence of amino acids

J

Which inference do these data support?
A Gene expression for chlorophyll is not affected by pollution.
B Plants in polluted areas can adapt in order to survive.
C Photosynthesis decreases in response to air pollution.
D Cellular respiration increases in plants in polluted areas.

C

Viruses can be transmitted through air, water, food, insect bites, and direct skin contact. Once a virus gains entry to the body, it invades a host cell in order to —
F deactivate the host cell’s defenses
G synthesize antibodies for defense
H metabolize host proteins and grow
J access cellular processes for replication

J

Which statement about the beetles in this environment is best supported by the data?
A Green beetles are more fit for the environment than brown beetles are.
B Brown beetles undergo a greater number of unfavorable mutations than green beetles do.
C Green beetles have a greater gene frequency among their population than brown beetles
have.
D Brown beetles have a shorter life cycle than green beetles have.

A

Photosynthesis and cellular respiration both involve the use and release of gases. Which statement correctly identifies the role of gases in the two processes?
F Photosynthesis and cellular respiration both use carbon dioxide and release oxygen.
G Photosynthesis and cellular respiration both use oxygen and release carbon dioxide.
H Cellular respiration uses oxygen and releases carbon dioxide, while photosynthesis uses carbon dioxide and releases oxygen.
J Cellular respiration uses carbon dioxide and releases oxygen, while photosynthesis uses oxygen and releases carbon dioxide.

H

Which statement provides the best evidence that Ambulocetus natans is an ancestor of Basilosaurus isis?
A Homologous structures occur in each fossil.
B Similar nitrogenous bases are found in the DNA of each fossil.
C The fossils were found in different locations.
D The youngest fossil is larger than the older fossils.

A

Which of these phrases could be placed in the position marked with an X?
F Provides nutrients to kidney cells
G Provides nutrients to brain cells
H Provides nutrients to nerve cells
J Provides nutrients to muscle cells

J

Which statement describes this model of DNA?
A The model is inaccurate because the base pairs are incorrect.
B The model is accurate because it contains correctly paired bases.
C The model is accurate because it shows each base splitting to form a double helix.
D The model is inaccurate because some typical bases in DNA are missing.

A

H

Which two trees are the most closely related?
A Taiwan beech and Taiwan catkin yew
B Taiwan catkin yew and lodgepole pine
C Lodgepole pine and Japanese maple
D Japanese maple and Taiwan beech

B

What causes this change in fur color?
F The alleles for fur color change as the arctic fox grows older.
G Gene expression for fur color is regulated by latitude.
H The arctic fox has two traits for fur color that are determined at birth.
J Gene expression for fur color is regulated by temperature.

J

Gel electrophoresis can be used to —
A determine the differences in ages of a set of people
B identify how closely two individuals are related
C determine how effective certain medications are
D identify different blood types

B

Which statement best explains the function of the vesicles?
F Delivering packaged materials to the Golgi apparatus for protein synthesis
G Exchanging genetic information between the Golgi apparatuses of separate cells
H Extracting portions of the Golgi apparatus to be regenerated for growth within the cell
J Transporting packaged molecules from the Golgi apparatus to be released out of the cell

J

Based on these data, this enzyme functions best at what temperature and pH?
A Temperature of 27°C and a pH of 4
B Temperature of 37°C and a pH of 6
C Temperature of 40°C and a pH of 8
D Temperature of 50°C and a pH of 10

B

The Indian leaf butterfly has traits that allow it to resemble a leaf. The bright colors of the monarch butterfly indicate that the butterfly tastes bad and can be poisonous.
How does the appearance of these butterflies help them to survive?
F The Indian leaf butterfly is able to avoid predators while the monarch butterfly warns predators away.
G The Indian leaf butterfly frightens predators away while the monarch butterfly poisons predators before they can eat it.
H Both butterflies rely on camouflage to avoid predation.
J Both butterflies cooperate with one another to avoid predation.

F

The female reproductive and endocrine systems work interactively for which main purpose?
A To maintain homeostasis by removing waste products from the body
B To release neurotransmitters during times of stress
C To control hormone levels to prepare the body for pregnancy
D To exchange gases to support cellular aerobic respiration

C

Which organism is the LEAST related to the other three organisms?
F Organism 1
G Organism 2
H Organism 3
J Organism 4

G

In the 1880s, Louis Pasteur developed a method of weakening viruses. The weakened viruses could be injected into healthy individuals.
How is this method effective in fighting viral diseases?
A The immune system develops antibodies in response to the weakened viruses.
B The weakened viruses attach to unaffected viruses in the host and interrupt the viral reproductive cycle.
C The rate of genetic mutation in the host is decreased due to the introduction of weakened viruses.
D Weakened viruses are unable to enter the host organism.

A

In humans blood type is determined by the A, B, and O alleles. The A and B alleles are codominant to each other and dominant over the O allele. An individual with the AO genotype and an individual with the BO genotype can produce offspring with which of the following phenotypes?
F O only
G A or B only
H A, B, or O only
J A, B, AB, or O

J

What is the role of mRNA in expressing specialized structures?
F Making energy available for cellular activities
G Creating bonds to form biomolecules
H Producing sugars that assist with replication
J Providing information to form proteins

J

Although these organisms belong to the same phylum, they are classified as different —
A families
B species
C kingdoms
D orders

B

A mutation in which types of cells would only affect the organism and not future generations?
F Egg cell and liver cell
G Sperm cell and egg cell
H Nerve cell and brain cell
J Sperm cell and lung cell

H

In the mid-1980s an aggressive strain of algae known as Caulerpa was accidentally introduced into the Mediterranean Sea when a seaside aquarium cleaned out its tanks. The algae contains a toxin that prevents native herbivores from consuming it. Caulerpa quickly spread over the sea floor, crowding out many species including sponges, corals, sea fans, and lobsters.
Which statement explains the most likely impact Caulerpa has had on the biodiversity in the Mediterranean Sea?
A The presence of Caulerpa within an ecosystem is an indicator of the ecosystem’s health.
B The spread of Caulerpa improved the habitat for many species of sea grasses, and increased the biodiversity.
C Caulerpa interbred with native species with the same adaptations within the ecosystem.
D Caulerpa became dominant within the ecosystem and reduced the biodiversity.

D

Which of these is the correct amino acid chain produced from the DNA template strand?
F Arginine -Leucine -Proline -Asparagine -Lysine -Arginine
G Tryptophan -Phenylalanine -Leucine -Glycine -Asparagine -Phenylalanine
H Serine -Leucine -Proline -Asparagine -Lysine -Arginine
J Tryptophan -Phenylalanine -Leucine -Glycine -Asparagine -Serine

F

Which statement best explains the importance of the root hairs to the stems and leaves of the plant?
A Root hairs convert minerals into glucose for immediate use by cells.
B Root hairs decrease the need for osmosis and diffusion in vascular tissue.
C Root hairs prevent water loss in leaves through transpiration and gas exchange.
D Root hairs increase the surface area of the roots for nutrient and water absorption.

D

A scientist shaved an area of white fur on the back of a Himalayan rabbit and placed an ice pack over the shaved area. The shaved area grew black fur.
Which of these best explains why the hair that grew back where the ice pack was placed was black and not white?
F The genes for black hair were activated by specific temperatures.
G The white hair mutated to black hair as the rabbit’s body temperature decreased.
H The coat color changed from white to black with the age of the rabbit.
J White hair only grows during certain times of the year.

F

A small town in the piney woods of East Texas has a soccer field composed of native grasses. The soccer field is mowed once a week.
What effect does continual mowing have on the ecology of the field?
A Mowing increases the likelihood of nonnative species displacing native species.
B Mowing increases the number of species found in the field.
C Mowing causes different types of communities to form across the field.
D Mowing maintains a low species diversity by inhibiting further succession.

D

H

The activities in the cell cycle occur during specific phases. In which phase of the cell cycle is DNA replicated?
A Mitosis
B G₁phase
C G₂ phase
D S phase

D

When constructing an energy pyramid of the swamp ecosystem, which of these would be placed at the top of the pyramid?
F Grass carp
G American alligator
H Eastern mud turtle
J Great blue heron

G

The white cattail is a hybrid species of plant that is a result of the cross between the broad-leaved cattail and the narrow-leaved cattail. Over time, the white cattail has established itself in the wetlands of Midwestern states.
Which of these explains the success of the white cattail?
A Favorable genes from parental generations provide advantageous characteristics to the hybrid species.
B Hybridization produces offspring traits that allow different species to survive in extreme environments.
C Inherited traits passed on from parental generations make hybrid species more susceptible to disease.
D Hybrid species display more adaptations due to their reduced genetic diversity.

A

An individual who participates in a long-distance run on a hot day will produce large quantities of sweat. As a result of the excessive sweating, the amount of urine produced by the kidneys will change.
How will the kidneys respond to help the individual’s body maintain homeostasis?
F The kidneys will decrease urine production so the body can maintain blood pH.
G The kidneys will increase urine production to eliminate excess salt in the body.
H The kidneys will decrease urine production to allow the body to conserve water.
J The kidneys will increase urine production so the body can absorb more nutrients.

H

The gray squirrel, Eastern fox squirrel, and red squirrel are all different species of squirrels. Why is having a scientific name for each species of an organism important?
A To prevent existing named organisms from having their names changed as they become extinct
B To keep the classification system from being altered as new organisms are discovered
C To allow organisms to be placed in many classification levels at the same time
D To standardize the naming and organization of organisms to avoid confusion

D

Which sample was most likely DNA?
F Sample 1
G Sample 2
H Sample 3
J Sample 4

F

Saprophytes are fungi that feed on dead and decomposing organisms. They secrete enzymes that digest components of cell walls, such as cellulose and lignin.
Which statement explains why these fungi are an important part of the biogeochemical cycle?
A Saprophytes perform gas exchange that assists the cellular activities of autotrophs.
B Saprophytes extract minerals from living tissue to recycle them back into the soil.
C Saprophytes transport nutrients through the xylem and phloem in autotrophs.
D Saprophytes return organic material to the soil for use by living organisms.

D

An advertisement for a health supplement for dogs claims to build lean muscle and strengthen tendons and ligaments, as well as provide energy. Which two biomolecules must the supplement contain to provide these benefits?
F Carbohydrates and lipids
G Proteins and carbohydrates
H Nucleic acids and carbohydrates
J Lipids and nucleic acids

G

Scientists have observed many types of tropical fish moving beyond their traditional ocean ranges into waters that have historically been more temperate. These fish compete for food with native fish, consuming much from the kelp forests and beds of sea grass.
The expansion of the ranges of tropical fish was most likely caused by —
A agricultural runoff that contributes to dead zones in the ocean
B global droughts that raise the salt concentration of ocean waters
C the rising temperatures of ocean waters
D acid rain pollution that lowers the pH of ocean waters

C

Which result is most likely to occur to the beetle population due to predation over time?
F The number of light-colored beetles in the population will increase.
G There will be more dark-colored beetles than light-colored beetles.
H The number of light-colored beetles will decrease.
J The dark-colored beetles will move to a different type of tree.

F

What is the probability of cloven hooves in the offspring of parents that are heterozygous for the trait?
A 25%
B 50%
C 75%
D 100%

C

Which of these must happen for corn seeds to develop on the ear?
F More tassels than silks need to be present on the same plant.
G Pollen grains must fall from tassels and land on the silks of the ear.
H Pollen must be transported from the tassel to the silk through the phloem.
J The tassels must come into direct contact with the silks of the ear.

G

Adaptations that result from natural selection are expected to increase the fitness of an organism. In terms of natural selection, which of the following best describes fitness?
A Being able to escape from predators
B Being among the strongest organisms in a population
C Being able to survive, find a mate, and produce offspring
D Being able to survive long enough to reach the adult stage

C

Which statement about the event represented in the diagram is valid?
F The event represents RNA translation in the smooth endoplasmic reticulum.
G The event takes place in bacterial cells.
H The event produces genetically identical daughter cells.
J The event provides genetic diversity in eukaryotic cells.

J

C

Which of the components could be observed using a microscope in a prepared slide of leaf epidermal cells but not in a prepared slide of human cheek cells?
F Components 2 and 3 only
G Components 3 and 4 only
H Components 1, 2, and 3 only
J Components 1 and 5 only

G

Niles Eldredge and Stephen Jay Gould researched the lenses of the eyes of fossil trilobites of different species. In 1972 they published a paper in which they described the tendency of a species to remain the same until a sudden change in the environment causes a new related species to appear.
Which hypothesis was most challenged by the work of Eldredge and Gould?
A Redi’s hypothesis that spontaneous generation does not occur
B Haeckel’s hypothesis that embryological development mimics the evolution of species
C Wallace’s hypothesis that geography affects the distribution of species
D Darwin’s hypothesis that the development of species is a slow, gradual process

D

Which part of a DNA molecule is responsible for the direct coding of specific traits in an organism?
F The number of hydrogen bonds that hold the strands of DNA together.
G The number of carbons in the DNA molecule.
H The sequence of nucleotide bases in the DNA molecule.
J The sequences of phosphates along each DNA strand.

H

When mammals get an infection, their internal body temperature often rises 2 to 3 degrees Celsius. The body gets the energy it needs to react to an infection by —
A increasing the rate of cellular division
B decreasing the rate of glucose movement into the cell
C increasing the rate of cellular respiration in mitochondria
D decreasing the rate at which carbon dioxide is removed from the cell

C

Scientists use zebra fish to study human genetic diseases because zebra fish and humans share many of the same genetic diseases.
Which statement describes why zebra fish experience similar genetic diseases as humans?
F Zebra fish have an omnivorous diet similar to that of humans.
G Zebra fish have nucleotide sequences similar to those of humans.
H Zebra fish go through embryonic stages similar to those of humans.
J Zebra fish produce gametes through a process that is similar to that of humans.

G

How do the circulatory system and immune system work together to respond to an injury?
A Increased blood flow kills healthy cells which prevents infection at the site of the injury.
B Increased blood flow removes infected cells from the body at the site of the injury.
C Increased blood flow carries white blood cells to the site of the injury.
D Increased blood flow allows for an increase in the exchange of O2 and CO2 at the site of the injury.

C

G

A student studying primary succession should focus on which of these communities?
A Open oak woodland
B Mesquite grassland
C Floodplain
D Granite rock

D

Based on this cladogram, which statement best describes relationships among millipede orders?
F Stemmiulida is more closely related to Merocheta than Penicillata is to Merocheta.
G Spirostreptida is more closely related to Glomerida than Sphaerotheriida is to Glomerida.
H Polyzoniida is more closely related to Glomeridesmida than Sphaerotheriida is to Glomeridesmida.
J Merocheta is more closely related to Glomeridesmida than Glomerida is to Glomeridesmida.

F

Which of the following best describes these biomolecules?
A Molecule X and Molecule Y are both carbohydrates.
B Molecule X is a nucleic acid, and Molecule Y is a carbohydrate.
C Molecule X and Molecule Y are both nucleic acids.
D Molecule X is a carbohydrate, and Molecule Y is a nucleic acid.

D

In North American forests, two species of birds, nuthatches and brown creepers, forage on the same trees for insects. Brown creepers feed on insects found near the bottom of the tree trunk, while nuthatches feed on insects in the top part of the tree.
The difference in foraging behavior most likely affects the nuthatches and brown creepers by —
F allowing the birds to avoid many types of predators
G reducing competition between the birds for resources
H preventing the birds from interbreeding with each other
J establishing dominance between the birds for nesting sites

G

Fruits grown in hot climates are usually less sweet than those grown in cooler temperatures. The high temperatures increase the rate of respiration in the plants, thus reducing the sugar content in some fruits.
Why does increased respiration in the leaves and stems reduce the sugar content in the fruits of a plant?
A Chloroplasts move from the fruits to the leaves and stems to provide energy
for respiration.
B The flow of nutrients shifts from the phloem to the xylem, moving nutrients away from the fruits.
C Sugars are moved from the fruits to the roots for storage.
D Sugars produced in the leaves are used as an energy source instead of being stored in fruits.

D

What do the two arrows represent?
F Arrow 1 represents prophase, and Arrow 2 represents interphase.
G Arrow 1 represents mitosis, and Arrow 2 represents meiosis.
H Arrow 1 represents interphase, and Arrow 2 represents mitosis.
J Arrow 1 represents meiosis, and Arrow 2 represents prophase.

H

Which statement explains how producers are dependent upon consumers for their survival?
A Consumers supply oxygen for producers to undergo aerobic respiration.
B Consumers produce carbon dioxide for producers to use during photosynthesis.
C Consumers provide chemical energy needed by producers for cellular respiration.
D Consumers make lactic acid that producers use in photosynthesis.

B

48 Which of these describes a difference between viruses and cells?
F Cells contain protein, and viruses contain only carbohydrates.
G Viruses have flagella, and cells have only cilia.
H Cells reproduce independently, and viruses require a host to reproduce.
J Viruses have membranes made of proteins, and cells have membranes made of nucleic acid.

H

As part of the nitrogen cycle, animals acquire some amino acids by doing which of the following?
A Breathing air
B Eating plants
C Drinking water
D Producing waste

B

Which two body systems must directly interact for vertebrate organisms to exchange gases?
F Skeletal system and muscular system
G Excretory system and reproductive system
H Circulatory system and respiratory system
J Digestive system and immune system

H

Which statement is best supported by the observable structures of the different humerus bones?
A The primates lived in similar environments.
B The primates shared a common ancestor.
C The primates interbreed with similar organisms in a population.
D The primates had diets that consisted of similar types of foods

B

Which of these mutations most likely results in the mutated hemoglobin gene?
F Insertion
G Deletion
H Duplication
J Substitution

J

Based on this food web, which organisms are direct sources of energy for secondary consumers?
A Aphid, Bird, Rabbit
B Ladybug, Fox, Dragonfly
C Frog, Butterfly ,Berries
D Mouse, Snake, Hawk

A

H