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?

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

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?

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?

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?

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?

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?

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 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?

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?

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?

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 —

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 —

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 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?

Lord Howe Island is a volcanic island in the Tasman Sea that is about 11 km long and 2.8 km wide. The island has two species of palm trees, Howea forsteriana and the more abundant Howea belmoreana. The two species do not interbreed even when they grow very close to each other. Which evolutionary process fails to occur?

Genome maps provide the DNA sequences of chromosomes. Some scientists have compared the genome maps of a hedgehog and a sloth. What do these genome maps allow the scientists to determine?

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 —

Which condition is essential for natural selection to result in a new species?

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 —

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 —

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?

After examining the fossil record, scientists have determined that scorpions today are much smaller than their extinct ancestors. For example, Jaekelopterus rhenaniae, a giant scorpion species that lived 255 million to 460 million years ago, was 2.5 meters long.

Which of the following conclusions is supported by this information?

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 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?

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?

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?

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?

The concept of gene flow is demonstrated when a cow is driven off from its herd, joins another herd, and reproduces. When the cow contributes to the gene pool of the new herd, which of these most likely increases?

Some organisms have genes that improve their ability to survive and reproduce. If the genes also help their offspring survive and reproduce, then which of the following will most likely increase?