The organisms represented by X are

A certain species of plant serves as the only food for the young larvae of a particular species of butterfly. In a large field, a disease kills all the members of this plant species. As a result of the plant disease, the butterfly population will most likely

When handling cat litter, humans can potentially be exposed to a harmful single-celled protozoan. Its primary host is the common domestic cat, but it can also live in humans. This protozoan is an example of a

Certain seaweeds contain a greater concentration of iodine inside their cells than there is in the seawater surrounding them. The energy required to maintain this concentration difference is most closely associated with the action of

Doctors sometimes use a vaccine to prepare the body to defend itself against future infections. These vaccines most often contain

An ameba is a single-celled organism. It uses its cell membrane to obtain food from its environment, digests the food with the help of organelles called lysosomes, and uses other organelles to process the digested food. From this, we can best infer that

White blood cells are most closely associated with which two body systems?

Carnivorous plants, such as pitcher plants and sundews, live in bogs where many other organisms cannot. Due to the high rate of decomposition occurring in bogs, the environment is acidic and contains very little oxygen and nutrients. The bogs only support certain types of organisms because

Anhidrosis is the inability to sweat normally. If the human body cannot sweat properly, it cannot cool itself, which is potentially harmful.

Anhidrosis most directly interferes with:

The hair colors of the members of a family are listed below.

mother – brown hair

father – blond hair

older son – brown hair

younger son – blond hair

The hair colors of the sons are most likely a direct result of

Carmine, a compound that comes from the cochineal beetle, shown above, is used as a food coloring.The food coloring is not harmful to most people, but in a small number of individuals, it causes a reaction and affects their ability to breathe. This response to carmine is known as

As a way to reduce the number of cases of malaria, a human tropical disease, a specific DNA sequence is inserted into the reproductive cells of Anopheles mosquitoes. Which process was most likely used to alter these mosquitoes? cloning studies

Some salmon have been genetically modified to grow bigger and mature faster than wild salmon. They are kept in fish-farming facilities. Which statement regarding genetically modified salmon is correct?

Which group of organisms in an ecosystem fills the niche of recycling organic matter back to the environment?

The use of solar panels has increased in the last ten years. A benefit of using solar energy would include

In a sewage treatment facility, an optimal environment is maintained for the survival of naturally occurring species of microorganisms. These organisms can then break the sewage down into relatively harmless wastewater. For these microorganisms, the wastewater facility serves as

The governments of many countries have regulations that are designed to prevent the accidental introduction of nonnative insects into their countries. This is because, in these new habitats, the nonnative insects might

The process of transferring energy during respiration occurs in a series of steps. This prevents too much heat from being released at one time. Maintaining an appropriate temperature is beneficial to an organism because

Fruits and vegetables exposed to air begin to brown because of a chemical reaction in their cells. This may result in these foods being thrown out. Some people have found that adding lemon juice (citric acid) to apple slices keeps them from turning brown. The prevention of browning is likely the result of

Which statement concerning an ecosystem is correct?

Energy for this ecosystem originally comes from

An environment can support only as many organisms as the available energy, minerals, and oxygen will allow. Which term is best described by this statement?

The reason that organisms can not produce populations of unlimited size is that

What impact do the amounts of available energy, water, and oxygen have on an ecosystem?

Knowing the type of food consumed by an organism helps to identify the role of the organism in the community. This role is known as its

Which statement best explains why the population stabilized?

Which sequence shows increasing complexity of levels of ecological organization?

Great horned owls and red-tailed hawks have similar requirements for food, space, and nesting materials. What would most likely be the result of great horned owls and red-tailed hawks living in the same community?

An ecosystem will most likely remain stable if

Cutting down a rain forest and planting agricultural crops, such as coffee plants, would most likely result in

Which statement best explains section X of the graph?

Many years ago, a volcanic eruption killed many plants and animals on an island. Today the island looks much as it did before the eruption. Which statement is the best possible explanation for this?

Species of animals that obtain food by consuming only autotrophic organisms are usually classified as

In a certain ecosystem, rattlesnakes are predators of prairie dogs. If the prairie dog population started to increase, how would the ecosystem most likely regain stability?

Imported animal species often disrupt an ecosystem because in their new environment, they will most likely

Vultures, which are classified as scavengers, are an important part of an ecosystem because they

The sequence of stages leading from bare field to stage D best illustrates the process known as

How much energy would be available to the organisms in level C?

The greatest amount of available energy is transferred from level

If the population of mice is reduced by disease, which change will most likely occur in the food web?

What is the original source of energy for this food web?

Which organisms are not shown in this diagram but are essential to a balanced ecosystem?

What type of cell is a plant cell?

What type of cell is a bacterial cell?

How do eukaryotes reproduce?

What is the smallest unit of an organism that can perform life functions?

There are three tenets of the Cell Theory. Which of the following is NOT a tenet?

Which of the following statements is true?

Energy for this ecosystem originally comes from

An environment can support only as many organisms as the available energy, minerals, and oxygen will allow. Which term is best described by this statement?

What impact do the amounts of available energy, water, and oxygen have on an ecosystem?

Which sequence shows increasing complexity of levels of ecological organization?

Great horned owls and red-tailed hawks have similar requirements for food, space, and nesting materials. What would most likely be the result of great horned owls and red-tailed hawks living in the same community?

Which organisms are not shown in this diagram but are essential to a balanced ecosystem?

Organisms that can make their own food are called

An organism that eats both plants and animals is a

Which of these is an abiotic factor?

What happens if a population grows past its carrying capacity?

Base your answer to the question on the information in the chart below and on your knowledge of biology.

How does the ability to produce 3000 to 6500 eggs benefit the species?

Scientists who have examined the fossil record have noted that some species have changed very little over long periods of geologic time. The lack of change in such organisms is most likely because

A variety of species of Galapagos finches evolved from one original species long ago through the process of

Base your answer to this question on the information below and on your knowledge of biology.

Fossil Footprints

Scientists examined a trail of fossil footprints left by early humans in soft, volcanic ash in Eastern Africa. A drawing of the trail of footprints is shown below. Each footprint is represented as a series of lines indicating the depth that different parts of the foot sank into the volcanic ash.

A researcher conducts an investigation on fiddler crabs to understand the importance of claw size in mating. The male fiddler crabs have one normal-sized claw and one giant claw that they wave to attract female fiddler crabs. The female fiddler crabs have two small, same-sized claws. The researcher places 15 male crabs with different sized claws into an enclosure with conditions similar to those in their natural habitat. The researcher then releases 15 female crabs into the enclosure. The graph shows the percentage of male crabs of different claw size that successfully mated for three successive trials. Select the statement(s) that correctly describe what the data in the graph shows.

The back of the Namib Desert darkling beetle, shown in the photograph below, is covered in little bumps that collect water from the air. When it tilts forward, the water runs off its back into its mouth.

These specialized structures on the beetle’s back allow it to

How does natural selection affect populations?

A biologist conducting a long-term field study noticed there were two types of mice in a valley. One type of mouse had webbed toes, and one type of mouse lacked webbed toes. A dam was built in the valley turning the land to wetland. As the years passed, all mice living in the valley were found to have webbed toes. No mice were found with non-webbed toes.

Which statement best explains the observed change in the mouse population?

Scientists have found an allele of a plant gene that may protect plants from some types of insects. To determine whether this allele is present in other plants of the species or is a recent mutation, they conducted the following experiment:

1. Isolate a sample of deoxyribonucleic acid (DNA) known to contain the allele from one plant that is unaffected by insects.

2. Isolate a sample of DNA that may contain the allele from three plants of the same species growing in the same location.

3. Treat the resistant DNA sample and the three DNA samples from the other plants with the same restriction enzymes to generate smaller segments of DNA.

4. Load and run a gel electrophoresis to separate the DNA segments.

5. Analyze the results of the gel electrophoresis.

Which DNA sample has the same allele as the resistant plant?

An example of a population in which evolution could take place in a relatively short period of time could be

A section of the mammalian evolutionary tree is shown.

Which number would indicate the most recent common ancestor of the hyrax, elephant, and manatee on the section of this mammalian evolutionary tree?

Gene mutations can be caused by many things. These mutations are biologically important because they

Which diagram below indicates that species D is more closely related to C than it is to either A or B?

Some orders of land and marine animals are closely related. Molecular data recently collected from dolphins, camels, deer, and hippopotamuses have shown that hippopotamuses are the closest living relatives of dolphins.

Which phylogenetic tree models this evolutionary relationship?

In the photograph , two fish are displaying a behavior commonly observed among pairs of rabbitfish. While one has its head down feeding on coral, the other remains upright, alert for predators.

This behavior continues to be present in the rabbitfish population because

Base your answer to the question on the information and diagram below and on your knowledge of biology. The diagram represents the evolutionary relationships among many organisms.

Three species with the most similar traits are most likely

Base your answer to the question on the information below and on your knowledge of biology.

Unique populations of giant tortoises live in the Galapagos Islands. This is the same group of islands where Darwin studied his famous finches. It is thought that the original ancestors of today’s giant tortoises came from the mainland of South America. These animals left and drifted in the ocean to the islands where they began to live, reproduce, and evolve. Each of the islands has a different habitat. Each species varies in shell shape and body structure. Information about two of these species of giant tortoises and their habitats is found in the table below.

When the saddle-backed tortoises extend their long necks out of the shell, they are unprotected from attack. Scientists hypothesize that during the evolution of this tortoise, they had few predators. Which statement best supports this hypothesis?