Taq polymerase is an enzyme used in the polymerase chain reaction (PCR) to replicate fragments of DNA. A study published in 1976 examined the properties of Taq polymerase after the enzyme was isolated from Thermus aquaticus, a thermophilic bacterium that lives in the hot springs of Yellowstone National Park. The graph shows one of the results of the study. Which statement about enzyme activity is best supported by this graph?

The graph shows the number of taxa of reptiles whose fossilized tracks have been found. Which statement is best supported by these data?

Some foods that are rich in complex carbohydrates can be difficult to digest. Gas often forms as the foods are slowly digested by bacteria in the large intestine. The advertisement is for a nutritional supplement that prevents intestinal gas. Which of the following represents evidence that could be used to support the claims about this product?

Researchers studying populations of lizards from the genus Gallotia on the Canary Islands compared the protein cytochrome b in different populations. The table shows the number of differences in the cytochrome b protein between different populations. Which conclusion about the relatedness of the lizards do these data support?

Simple leaves have a single leaf on a petiole, or stem, while compound leaves have more than one leaflet on a petiole. This unknown leaf can be identified using the dichotomous key. Which tree does the unknown leaf come from?

The diagram represents a theory about cells. Which theory is represented in this diagram?

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 —

Proteins and carbohydrates have many functions in the body of an organism. Specific proteins and carbohydrates perform specific tasks. Information about a protein and a carbohydrate is given below. How are ferritin and glycogen similar in their primary functions for an organism?

The table shows the survival rate of two types of beetles in the same environment over a period of three years. Which statement about the beetles in this environment is best supported by the data?

Cetaceans are whales and their relatives. The diagram shows some fossils of cetaceans. Which statement provides the best evidence that Ambulocetus natans is an ancestor of Basilosaurus isis?

The classifications of four trees are shown in the table. Which two trees are the most closely related?

The diagram represents one way an enzyme can be inhibited. Which statement explains the effect of an inhibitor on an enzyme?

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?

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 —

The quiver tree grows in desert areas in southern Africa. In recent decades average temperatures have been rising in southern Africa. Scientists predict that this warming trend will continue. Quiver trees in the hottest parts of their range near the equator are dying, but quiver trees at high elevations or in parts of the range that are farther from the equator are growing and reproducing. Which of these best explains what is happening to the quiver tree population in southern Africa?

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?

This dichotomous key can be used to identify some conifers. Based on the key, which of these best describes the leaves and cones of the longleaf pine?

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 —

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?

In the European roe deer (Capreolus capreolus), implantation of embryos after breeding is delayed. The deer breed in July or August but do not give birth until the following May or June. From summer to late December, the embryo rests in a state of dormancy as a 30-cell blastocyst. In late December or early January, the embryo sends a signal that causes the female to release hormones, allowing the embryo to continue to develop normally. Why is delayed implantation an advantageous adaptation for the European roe deer?

A student wants to use the Venn diagram below to show the characteristics of two kingdoms of organisms. The characteristics that the two kingdoms share will be listed in the shaded area where the circles intersect. Which of these is a characteristic that the student should list in the shaded part of the diagram?

An analysis of DNA and RNA sequences can be used to classify organisms. A dendrogram, such as the one shown below, is based on molecular data. It can be used to represent evolutionary relationships within a group of organisms that are hypothesized to have descended from a common ancestor. Which statement is best supported by the information in this dendrogram?

Adult mountain lions (Puma concolor) are almost 2 meters long. They have a black spot over each eye. The common names used throughout the United States for this species are listed below. Why is it best for scientists to use the name from the standardized taxonomic system?

A cladogram is shown below. All the animals to the right of the hagfish would have the common characteristic of —

Plants have developed many methods of seed dispersal. The table below shows seeds of two different plants. How has the seed dispersal method developed by these plants given them a reproductive advantage?

This diagram of the fossil record represents changes in mollusks over millions of years. How can the pattern of change in the fossil record best be explained?

Three species of lizards of the genus Gallotia are found on the Canary Islands, a chain of seven volcanic islands off the west coast of Africa. The easternmost island, Lanzarote, is the oldest, while the westernmost island, El Hierro, is the youngest. The distribution of lizard species is shown on the map below. Which statement about the ancestry of the lizards from the genus Gallotia is best supported by this information?

The opossum, which is native to North America, and the kangaroo, which is native to Australia, are marsupials. The fact that both these mammals incubate their immature offspring in a pouch provides evidence that they —

The cladogram shows the evolution of land plants as indicated by fossil records.Which discovery would challenge the validity of this cladogram?

Using a light microscope, a student identified the following characteristics of four organisms found in a sample of pond water. Based on the observations of the student, which organisms most likely belong to the taxonomic group for bacteria?

Lactose is found in milk products. It is converted by the body into a usable form in a series of chemical reactions. The diagram shows the series of reactions that convert lactose into a usable form. If Enzyme 2 is denatured, the levels of which substance will increase?

In Madagascar scientists have discovered a moth, Xanthopan morganii praedicta, that has a 30.5 cm proboscis and feeds from and pollinates Darwin’s orchid, Angraecum sesquipedale. The orchid has a nectar-producing tube that is 27.9 cm long. How is the moth’s proboscis size an adaptation for its environment?

Most plant leaves take in more carbon dioxide as light increases. They give off carbon dioxide if light intensity is too low. The graph shows a plant’s carbon dioxide levels at different light intensities. At point X, the rate of which process is equal to the rate of photosynthesis?

Pepsin and trypsin are two of the digestive enzymes that break down protein. A group of students studied the pH requirements of these enzymes. The graph below shows the results. The students found that pepsin functions best in an acid environment and trypsin functions best in a neutral environment. Based on their observations, pepsin most likely aids in digestion in which part of the human body?

The diagram shows a dichotomous key and a picture of a fruit. According to the key, the fruit comes from which species of tree?

A student collected the animal shown below on a field trip. The student used a dichotomous key and a microscope to classify the animal. How should this animal be classified?

Zoogeographic regions are characterized by the presence of specific groups of animals. These regions are determined by the taxonomic or phylogenetic relationships of animals. The map shows the zoogeographic regions proposed by the naturalist Alfred Russel Wallace in 1876. The similarities of organisms in which two areas numbered above provide the best evidence for common ancestry between the organisms in both locations?

A harmless scarlet king snake and a venomous eastern coral snake have similar band patterns, as shown below. For the scarlet king snake, the adaptation of having a banding pattern like the eastern coral snake’s is known as mimicry. The outcome of this adaptation in the scarlet king snake is to —

The limbs of several organisms are shown in the illustrations below. Scientists sometimes compare the limbs of these organisms to look for evidence of common ancestry. These limbs provide evidence of common ancestry because they —

The diagram shows taxonomic groups and a major distinguishing characteristic of all but two of them. Which characteristics will be used to complete the chart?

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?

Scientists can determine relatedness among organisms by comparing partial amino acid sequences. The table shows four partial amino acid sequences from four organisms. Which organism is the LEAST related to the other three organisms?

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 -

Which list correctly identifies characteristics that protists share with animals?

The diagram shows light- and dark-colored beetles that live on a tree. Which result is most likely to occur to the beetle population due to predation over time?

The relationships among different orders of millipedes are shown in the cladogram.Based on this cladogram, which statement best describes relationships among millipede orders?

Two biomolecules are shown. Which of the following best describes these biomolecules?

The image shows part of the humerus bone in different genera of primates. Which statement is best supported by the observable structures of the different humerus bones?