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1
1.
A new predator of rabbits has been introduced within an ecosystem. This new predator runs faster than the native predators of rabbits.
Which statement describes what will most likely occur in the rabbit population due to the introduction of the predator?
B.C.7E
B.C.2G
1
2.
Which answer choice best describes a community?
B.C.10C
1
3.
Eight components present in nucleic acids are listed in the box.
Which components bond with adenine in a section of double-stranded DNA?
B.C.6A
B.C.2G
1
4.
What would be the most likely effect of a wildfire that burned a large area of a forest?
B.C.12D
1
5.
Which four body systems interact to allow a person to sneeze?
B.C.10A
1
6.
Students use a microscope to look for structures present in four different cells. The students placed an X for each structure that was viewed for each cell on the table shown.
Which cell that was viewed is most likely a prokaryote?
B.C.4A
B.C.2H
1
7.
A dichotomous key for identifying fish is shown.
Based on this key, which two fish have eyes located on either side of their head and are not spotted?
B.C.8B
B.C.2H
1
8.
Students are modeling mRNA during the process of protein synthesis. Which answer choice correctly describes the model of the mRNA strand being transcribed?
B.C.6C
B.C.3E
1
9.
The karyotype, or chromosomal profile, for humans is shown. A karyotype can be used to investigate genetic disorders.
The chemical colchicine is used in the production of karyotypes. Colchicine prevents spindle fibers from forming during the cell cycle.
What is a result of preventing spindle fibers from forming?
B.C.5A
B.C.3D
1
10.
A team of students encounters an unknown organism in a field while conducting a biodiversity study. Some students think the organism is a plant, while others think it is a fungus.
Which question should the students investigate to classify the organism correctly?
B.C.8C
B.C.2E
1
11.
The San Marcos salamander, Eurycea nana, is a light reddish-brown translucent salamander about 2–5 cm in length. E. nana is found only in Spring Lake and a portion of the San Marcos River.
Which human activity would most likely decrease the ability of the salamanders to survive?
B.C.12E
1
12.
The diagram shows data on the evolution of horses.
The data in the diagram is evidence that —
B.C.7B
B.C.2G
1
13.
A student produces a labeled drawing of a virus for a presentation. The student states that the capsid has a function similar to the nuclear membrane found in animal cells.
Which of these describes the similar functions of capsids and nuclear membranes?
B.C.4C
B.C.2H
1
14.
Enzymes are proteins that have a three-dimensional shape that is specific to a particular substrate. Environmental conditions can change the shape of the protein.
What is the most likely result if the shape of the enzyme changes?
B.C.9C
1
15.
A type of cellular transport is shown.
Which description best identifies this type of cellular transport?
B.C.4B
B.C.2H
1
16.
The aye-aye lemur is a mammal that feeds mostly on insect larvae that live inside trees. The aye-aye lemur has a specialized middle finger that is long and thin. The aye-aye lemur moves along a tree branch and taps the branch with its specialized finger. When the aye-aye lemur hears a difference in the echo, it will tear open the bark with its teeth until the insect tunnel is exposed. The aye-aye lemur then uses its specialized finger to reach the insect larvae and remove it.
Which selective pressure most likely resulted in the development of the aye-aye lemur’s special adaptation?
B.C.7E
1
17.
Mice have two unlinked allele pairs that affect fur color. The table shows how allele pairs affect fur color. The term “agouti” describes fur with pigmentation that changes in each hair from the shaft to the tip, giving the fur a banded appearance. Mice with the aa allele pair are albino, regardless of the second allele-pair combination.
What is the probability of albinism in the offspring of a cross between two mice with AaBb alleles?
B.C.6F
B.C.2.f
1
18.
Gibberellins are hormones produced in the root tips of plants. The plant uses these hormones to stimulate the growth of shoots.
How are gibberellins able to affect other parts of the plant?
B.C.10B
1
19.
The diagram shows molecules that a mitochondrion uses and produces during a cellular process.
Which other molecule is a product of this process?
B.C.4B
B.C.2H
1
20.
A partial Texas food web is shown
The populations of which organisms will most likely increase as a result of a disease that suddenly reduced the population of Texas horned lizards?
B.C.12C
B.C.2H
1
21.
A biomass pyramid of an ecosystem is shown.
Which statement provides the best explanation for the difference in biomass of organisms found at each trophic level?
B.C.12C
B.C.2H
1
22.
Conservation biologists studying cheetah populations have determined that the lack of genetic diversity among the cheetahs is due to genetic drift.
Which statement explains the most likely consequence of having a low genetic diversity on the cheetah population?
B.C.7F
B.C.3D
1
23.
CRISPR-Cas9 is a genetic modification technique that edits parts of the genome of an organism. Using this technique scientists can add, remove, or modify sections of the DNA sequence.
How can scientists use this technique to control gene expression?
B.C.6D
B.C.3D
1
24.
During secondary succession, which of these best describes why decomposing pioneer plants give way to larger, more complex plants species, such as hardwood trees?
B.C.11B
1
25.
The fuzzy millipede, Polyxenus fasciculatus, is found in Texas and is preyed upon by most species of ants. To protect itself against the ants, it ejects fibers from a tuft located at the tail end of its body. The tufts have hooks at the tips and barbs along their length that lock and interlink with the ant’s setae, small hairs that cover the body of the ant. When an ant attacks, the millipede flexes its back end toward the ant and wipes the tufts against it. As the ant attempts to remove the tufts, it entangles itself more, becoming immobilized.
Which two systems most directly interact in the fuzzy millipede’s defense against ants?
B.C.10A
B.C.2H
1
26.
The inheritance pattern for an autosomal dominant trait is shown in the pedigree. Shaded symbols represent individuals that express the dominant trait.
Based on this pedigree, what are the most likely genotypes of individuals I-1 and I-2?
B.C.6F
B.C.2G
1
27.
When cells lose their ability to regulate the cell cycle, they can divide at an accelerated rate and form a mass of cells. This mass of cells is referred to as —
B.C.5C
1
28.
The model shows a mutation to a partial sequence of bases in a gene.
Which type of mutation does the model demonstrate?
B.C.6E
B.C.2G
1
29.
Many tree frog populations are threatened due to habitat loss. In an effort to promote conservation, tree frogs may be bred in captivity. A zoo acquired male and female tree frogs from two different populations. In the zoo, the tree frogs were able to successfully mate within their own population, but breeding attempts between the two populations were unsuccessful.
Based on this information, which statement correctly describes the relationship between the two populations of tree frogs?
B.C.8B
B.C.3D
1
30.
In a study of physical endurance, researchers observed significant increases in the heart rates and breathing rates of participants immediately after they engaged in strenuous exercise.
Which statement best explains the increase in the heart rate and the breathing rate during exercise?
B.C.4B
B.C.3B
1
31.
In 1898 Friedrich Loeffler and Paul Frosch found evidence that the cause of the highly contagious hoof-and-mouth disease in livestock was a microscopic infectious particle. It was discovered that this particle requires a host cell to reproduce.
Which pathogen is most likely responsible for causing hoof-and-mouth disease in livestock?
B.C.4C
B.C.3F
1
32.
The diagrams show a partial food web containing the Glyptapanteles wasp and the life cycle of this wasp.
Based on the two diagrams, which list correctly identifies the relationships Glyptapanteles wasp larvae have with other organisms?
B.C.12A
1
33.
Male guppies found in areas without predators are more colorful than the ones found in locations with large predator populations. A population of adult guppies originating from an area with a large number of predators is transferred to a nearby area with few predators.
Which of these is most likely to happen over a few generations?
B.C.7C
1
34.
Grassland ecosystems in Texas have evolved to depend on periodic fires to return nutrients to the soil and encourage plant reproduction. Humans have prevented fires in many of these grassland areas, resulting in plant and animal communities with little diversity. Wildlife biologists often recommend purposefully starting fires called prescribed burns, which are monitored and controlled, in grassland ecosystems every 3 to 4 years. These biologists observe greater diversity in plant and animal life in the years following a prescribed burn.
What natural processes are the biologists attempting to imitate?
B.C.11B
B.C.3D
1
35.
A chart of some plant systems and functions is shown.
Which system interactions are dependent on the plant’s ability to respond to the direction of light?
B.C.10B
B.C.2G
1
36.
Exposure to the building material asbestos has been linked to certain types of cancers. Asbestos causes mutations in the p53 gene, which controls tumor suppression.
Which statement best explains why people with cancer due to asbestos exposure do not pass the mutation on to their offspring?
B.C.6E
B.C.3D
1
37.
Which of these components are found in the cells of all living organisms?
B.C.6B
1
38.
A feedback mechanism in the human body is shown.
Based on this diagram, which two systems interact to maintain homeostasis?
B.C.10A
B.C.2H
1
39.
Which role of protists has the most positive effect on maintaining the plant population in an ecosystem?
B.C.11A
1
40.
A table of four types of carbohydrates is shown.
Which list correctly matches the functions to the types of carbohydrates?
B.C.9A
B.C.2G
1
41.
Gametes produced by an organism contain a combination of genes from that organism. In every gamete, this combination is —
B.C.6G
1
42.
White-tailed deer are seasonal breeders. Female white-tailed deer begin their reproductive cycle in the fall. Rising testosterone levels in male white-tailed deer cause them to start their breeding season around the same time. Offspring are born the following spring and summer.
What is the most likely explanation for white-tailed deer having a seasonal breeding cycle instead of a monthly breeding cycle like many domesticated animals?
B.C.7D
B.C.2G
1
43.
A segment of a DNA strand is shown.
3’ AGGTCAGGT 5’
Which of these is the correct complementary DNA strand for the segment shown?
B.C.6A
1
44.
The ocean sunfish (Mola mola) is a large, flat fish that spends most of its time in deep water feeding mainly on jellyfish. Sunfish often have many species of copepods, small crustaceans, that bury their heads into the soft tissue of the sunfish. Sunfish will swim to the surface of the water and lie sideways, allowing seabirds to eat the copepods from their skin.
Which list describes the types of relationships the sunfish has with other marine organisms?
B.C.12A
1
45.
Which statement accurately describes the energy needs for photosynthesis and cellular respiration?
B.C.9B
1
46.
Which table shows two steps of DNA replication?
B.C.5A
B.C.2G
1
47.
This cladogram shows the evolutionary relationships among some mammals based on homologous structures.
Which statement is supported by this cladogram?
B.C.7A
B.C.2H
1
48.
Some species of millipedes will roll into a ball when threatened, while other species of millipedes can secrete noxious chemicals from their bodies.
These adaptations allow the millipedes to —
B.C.12B
1
49.
The diagram shows how specialized body cells can develop.
Which of the following best explains why cells that contain the same genetic material do not develop into the same types of cells?
B.C.5B
B.C.3A
1
50.
Transmembrane proteins span the width of cell membranes. Four types of transmembrane proteins are shown in a section of cell membrane.
Although these proteins have different specific functions, they all —
