Scientists estimate that there are more than 20,000 species of ants. The species range in size from 1 mm long to 38 mm long and live in most environments. The diets of ants range from flowers and seeds to fluids from their own larvae. Ants have been able to successfully inhabit so many different environments because their populations have been able to --

Two populations of mice living in the same forest are separated by a large water-filled ditch. After a rainstorm, flooding brings several mice from one population to the other population. When the mice from the first population reproduce with members of the second population, which of the following will likely occur?

The picture shows bean-shaped glands called nodes. The clusters of cells in the nodes include macrophages that break down viruses and other potentially harmful materials. Nodes also contain cells that produce protein particles capable of capturing harmful materials that flow in tissue fluid through the nodes. Different parts of the body are drained by nodes in different regions of the body.

Which body systems are directly responsible for regulating these nodes and protecting the body from harmful materials in tissue fluid?

Organisms are classified today using the Linnaean system, and the following table shows the taxonomic classification of two marine organisms living along the Pacific Coast.

Taxonomic classification is important to marine biologists because it provides a way to -

When a person is suddenly cut by a sharp object, a nervous impulse is sent along a sensory neuron to the spinal cord. The impulse is immediately transmitted through motor neurons to produce a response. Which of the following correctly identifies and describes this response?

A student conducted an investigation to study phototropism in grasses. The only difference between the control group and the experimental group was the light conditions. The control group was provided full light, while the experimental group was shaded on one side. The diagrams show the average heights and positions of blades of grass in the investigation. (View Image)

Which statement best explains why the grass tips of the experimental group bent toward the light?

Part of an important cellular process involving a DNA strand is modeled in the image. (View image)

What is the purpose of this cellular process?

The energy pyramid shows the energy made available by producers. (View Image)

Base 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?

Nitrogenous bases are located on both strands of the DNA double helix. What is the significance of the nitrogenous bases?

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?

Some students used vinegar to dissolve away the shells of three eggs and used the eggs as models of human red blood cells. The students observed the changes in the eggs when they were placed in different solutions. (View Image)

Which statement best describes the role of the cell membrane in this model?

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 --

The diagram shows cells in different phases of mitosis. A student is trying to find a cell in a particular phase of mitosis. The student is looking for evidence that spindle fibers are separating the chromosomes to ensure that each new nucleus has one copy of each chromosome. (View Image)

Which cell is in the phase of mitosis that the student is searching for?

Albinism is an autosomal recessive condition. Which circle graph shows the genotype probability when an albino female mates with a male that is heterozygous for the albinism trait? (View Image)

Photosynthesis and cellular respiration both involve the use and release of gases. Which statement correctly identifies the role of gases in the two processes?

The diagram represents one way an enzyme can be inhibited. (View Image)

Which statement explains the effect of an inhibitor on an enzyme?

Four common relationships between organisms are listed in the box. (View Image)

Which statements best describe these relationships?

The four butterflies in the illustration represent the offspring in the F₁ generation. Which statement is best supported by the phenotypes of these offspring?

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?

Four different nucleotides are used as building blocks of DNA. Which of the following can be used to distinguish one nucleotide from another?

The green frog (Lithobates clamitans clamitans) is found in many parts of the United States. The table contains some information about this frog. Why does the ability to lay 1,000 to 5,000 eggs increase the fitness of the species L. clamitans clamitans?

Food webs such as the one shown were first used in 1927 by the animal ecologist Charles Elton. The food web below represents the feeding relationships among organisms in an Alaskan ecosystem. An environmental change that removed which of these organisms from the ecosystem would cause the most instability in the ecosystem?

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?

During meiosis, homologous chromosomes exchange genetic material. This exchange of genetic material

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

Which statement best describes the relationship between the products of photosynthesis and the reactants in cellular respiration?

The initial steps in gene expression are modeled. Double-stranded DNA first unwinds into two strands. Which process and product are represented in the diagrams?

Some relationships between different organisms are shown in the table. Which table correctly identifies each type of interaction described?

A prey population consists of individuals with a variety of running speeds. The adaptation that allows some of these animals to run fast would be an example of natural selection if it helps them--

Nitrogenous bases are located on both strands of the DNA double helix. What is the significance of the nitrogenous bases?

The diagram shows cellular activity across a cell membrane. Which two processes does this diagram most directly model?

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?

Part of a hydrothermal vent food web is represented in the diagram. Which organisms are both secondary and tertiary consumers in this food web?

Five general characteristics of organisms in kingdoms Plantae or Fungi are listed in the box. Which table correctly lists the characteristics of the organisms in the two kingdoms?

Several structures work together to allow flowering plants to reproduce. The diagram shows a typical flower. Which table correctly identifies the function of each structure or group of structures in the reproduction of the plant?

The table shows a DNA sequence and three types of mutations that can change the DNA sequence. Which mutation will cause translation to stop?

The picture shows a 3-D model of a virus called a bacteriophage. Bacteriophages can infect

bacteria such as E. coli. In what way are the bacteriophage and E. coli alike?

The complex carbohydrates pictured below are made by linking molecules of glucose. In all three complex carbohydrates, the subunits of glucose are bonded together differently. Because they have different structures, they most likely —

The table shows some observations made by four students during a field trip to a nature area. Which student made observations of a community of organisms?

Each strand of a DNA molecule contains nitrogenous bases that pair with other nitrogenous bases in very specific ways. A diagram of a section of DNA is shown. Which DNA strand is complementary to the one shown above?

Nudibranchs are marine gastropods that lack shells. Many of these gastropods retain the foul-tasting poisons of their prey and secrete them when threatened. The bright coloration of the nudibranchs warns predators to avoid them. Based on this information, how has adaptation allowed marine gastropods to be successful without a shell?

A section of a nucleic acid is shown below. The process represented in the diagram produces a molecule that is complementary to the template strand of DNA. What type of molecule is produced?

If several pea plants with the genotype TTYy are crossed with pea plants with the genotype Ttyy, what percentage of the offspring will be expected to have the TTYy allele combination?

A photomicrograph of onion root tip cells during mitosis is shown below. Which phase of mitosis is occurring in the cell indicated by the arrow?

A model of a DNA molecule is shown below. The arrow indicates —

Crossing-over between nonsister chromatids during meiosis is significant in heredity. This process most likely leads to an increase in which of the following?

The picture below is an example of _________________.

The scenario above is best described by the interaction of what three body systems?

A deer hears a predator approaching and begins to run for safety. The deer has primarily engaged what body systems to escape?

The diagram above represents an example of how the body regulates itself. This diagram describes what relationship in body systems?

When one side of a plant is not getting enough light, a hormone is produced in the shoot system causing growth on the darker side of the plant. This growth on the darker side causes the plant to bend. This is an example of:

Health-care workers are exposed to many different types of pathogenic and nonpathogenic microorganisms. Which body systems work together to protect the body from pathogens?

Leaves are part of a plant’s shoot system. The xylem tissue in leaves transports —

Plant hormones serve as chemical messengers between cells and tissues. Auxin is a plant hormone that causes the cells on the shady side of a plant shoot to elongate. The response enabled by auxin is known as —

Copper is a micronutrient that can be found in soil. Copper is important for reproductive growth in plants and plays an indirect role in chlorophyll production. Which statement correctly describes the interaction that occurs between the root and the shoot systems of plants to allow reproduction to occur?

Some students are instructed to put a celery stalk in a red dye solution for a lab activity. First the students carefully cut the bottom of the stalk with a scalpel. Then they put the stalk in the beaker with the solution and place the beaker on a shelf in the lab room. The next day they check the stalk and make observations. The students note that the leaves at the end of the stalk have changed color from green to red. The students cut across the celery stalk and use a hand lens to see that the small tube openings along the edge of the celery stalk are also red. The cross section is shown below.

How do the plant systems work together to make this movement of liquid possible?

The outermost layer of plant stems in dicotyledons consists of epidermal cells and guard cells that surround openings called stomata. The epidermal cells are usually covered with a waterproof layer that provides protection from injury and water loss. The stomata allow gas exchange. The epidermal cells and stomata have functions similar to those of which two human body systems?

In Holstein cattle the allele for black hair color (B) is dominant over the allele for red hair

color (b), and the allele for polled (P), or lacking horns, is dominant over the allele for having

horns (p).

What is the expected phenotypic ratio of the offspring of a BbPp × BbPp cross if these alleles

sort independently?

A segment of DNA produces methionine, threonine, histidine, aspartate, and glycine when translated. A substitution mutation occurs and causes the synthesis of the segment as shown. Which is the new peptide chain when the new DNA segment is translated?

The model represents the change in the DNA content of a cell during the cell cycle. Which part of the model represents the S phase?

Facial dimples and free earlobes are both considered dominant human traits. What are the expected phenotypes of the offspring of a female with dimples and free earlobes (DDFf) and a male with no dimples and attached earlobes (ddff)?

Models of the human immunodeficiency virus (HIV) and an animal cell are shown. What is the difference in function of the glycoprotein structures of an HIV virion and the cilia of an animal cell?

The results shown in the picture were obtained using a technique known as gel electrophoresis. This technique separates mixtures of DNA. In the picture nine different samples of DNA are compared.

The diagram illustrates the activity of vesicles during a cellular process.

Which statement best explains the function of the vesicles?

The graphs show the reaction rate for an enzyme across a range of temperatures and pH.

Based on these data, this enzyme functions best at what temperature and pH?

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?

A student used a microscope to study four members of the phylum Ciliophora. Members of this phylum move when propelled by hundreds of tiny cilia.

Although these organisms belong to the same phylum, they are classified as different

A mutation in which types of cells would only affect the organism and not future generations?

Which list correctly identifies characteristics that protists share with animals?

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?

A corn plant produces both male and female flowers. The male flower forms the tassel and the female flower forms the ear of corn. The silks that emerge from the ear are the stigma of the female flower. Each silk leads to an ovule that can become a corn seed.

Which of these must happen for corn seeds to develop on the ear?

Some components of cells are listed.

1. Cytoplasm

2. Nucleus

3. Chloroplasts

4. Cell Wall

5. Cell membrane

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?

A student groups different types of cells as shown.

Which table headings should the student use for the two groups?

This model of the cell cycle includes two arrows that each represent a process in the cycle.

What do the two arrows represent?

As part of the nitrogen cycle, animals acquire some amino acids by doing which of the following?

A certain mutation in the gene for hemoglobin results in the red blood cells becoming sticky, rigid, and irregularly shaped. These irregularly shaped red blood cells block the flow of blood throughout the body. A single base mutation is responsible for these irregularly shaped blood cells.

Which of these mutations most likely results in the mutated hemoglobin gene?