Finch beak depth was measured before and after a severe drought in 1977. The averaged results are shown in Figure 1. After the drought, there were fewer seeds available for the finches to eat and the seeds that did remain were larger and harder to crack open. Researchers claim that when large, hard seeds are the predominate food source, the average beak depth of these finches tends to increase in subsequent generations. The horizontal axis is labeled Beak Depth, in millimeters, and the numbers 7.3 through 11.3, in increments of 0.5, are indicated. The vertical axis is labeled Number of Birds, and the numbers 0 through 50, in increments of 10, are indicated. For most values indicated along the horizontal axis there are two bars. A key indicates that one bar represents values Before the 1977 drought and one represents values After the 1977 drought. The data represented by the histogram are as follows. Note that all values are approximate. Beak Depth, 7.3 millimeters. Before the 1977 drought, 1 bird. After the 1977 drought, 0 birds. Beak Depth, 7.8 millimeters. Before the 1977 drought, 13 birds. After the 1977 drought, 1 bird. Beak Depth, 8.3 millimeters. Before the 1977 drought, 30 birds. After the 1977 drought, 3 birds. Beak Depth, 8.8 millimeters. Before the 1977 drought, 47 birds. After the 1977 drought, 3 birds. Beak Depth, 9.3 millimeters. Before the 1977 drought, 45 birds. After the 1977 drought, 7 birds. Beak Depth, 9.8 millimeters. Before the 1977 drought, 40 birds. After the 1977 drought, 9 birds. Beak Depth, 10.3 millimeters. Before the 1977 drought, 27 birds. After the 1977 drought, 10 birds. Beak Depth, 10.8 millimeters. Before the 1977 drought, 3 birds. After the 1977 drought, 1 bird. Beak Depth, 11.3 millimeters. Before the 1977 drought, 0 birds. After the 1977 drought, 0 birds. Figure 1. Finch beak depth before and after the 1977 drought. Using the evidence provided, which of the following best justifies the researchers’ claim?

_______ is the process in which a protein is assembled at a ribosome.

The amino acid sequence of cytochrome c is exactly the same in humans and chimpanzees. There is a difference of 13 amino acids between the cytochrome c of humans and dogs, and a difference of 20 amino acids between the cytochrome c of humans and rattlesnakes. Which of the following statements is best supported by these data?

Which of the following correctly compares the two processes shown above? The first process is fertilization. A sperm fusing with an egg is shown. The second process is transduction. A five step process is shown. Step 1. Virus attaches to cell surface and inserts viral DNA into cell. Step 2. The cell’s circular DNA is broken into many pieces. Step 3. new viral particles are formed in the cell that include DNA from the host cell. Step 4. One of the new viral particles infects another cell. Step 5. The DNA from the virus is inserted into the circular chromosome of the shot cell.

Which of the following is NOT one of the ways an individual organism can respond to external environmental changes?

Which of the following observations best supports the hypothesis that a large object collided with Earth in a period of time associated with a mass extinction?

A current challenge for doctors involves the bacterial strain Clostridioides difficile, which no longer responds to traditional antibiotic treatments. Which of the following best explains why this particular strain of bacteria is resistant to antibiotic treatment?

Stickleback fish are found in both marine and freshwater habitats. The marine fish have no scales but have hardened, armorlike plates along their sides. The plates are thought to protect sticklebacks from certain predators. In the late 1980s, sticklebacks from a marine population colonized Loberg Lake, a freshwater lake in Alaska. Starting in 1990, researchers sampled fish from the lake every four years and recorded the armor-plate phenotypes of the male sticklebacks in each sample. The armor-plate phenotypes were categorized as either complete (plates extending from head to tail), partial (plates extending from head to abdomen), or low (a few plates near the head only). The results are shown in the table below. ARMOR-PLATE VARIATION IN THE STICKLEBACK POPULATION OF LOBERG LAKE Percent of Males in the Sample with Each Armor-Plate Phenotype Year Low Partial Complete 1990 1% 2% 97% 1994 45% 14% 41% 1998 58% 16% 26% 2002 76% 15% 9% 2006 90% 6% 4% Which of the following best explains the changes in the phenotype frequencies of the stickleback population in Loberg Lake?

All of the following are density-dependent factors that limit animal populations EXCEPT

African elephants, Loxodonta africana, are often hunted illegally for their tusks. Both male and female elephants have tusks, although the tusks are much larger in the males. Researchers have followed the elephant population in Gorongosa National Park in Mozambique for many years. Figure 1 shows the percent of tuskless female elephants expected in wild populations throughout the species’ range, as well as the percent of tuskless females that survived the hunting between 1977 and 1992 (those over 25 years old) and the percent of female elephants born after 1992 without tusks in the park. The data are based on 200 known female elephants in the park. There are 3 categories indicated along the horizontal axis: Wild Population, Females Older Than 25, and Females Born After 1992. The vertical axis is labeled Percent of Tuskless Females, and the numbers 0 through 100, in increments of 20, are indicated. The following data is represented by the graph. Wild Population, 4 percent of Tuskless Females. Females Older Than 25, 51 percent. Females Born After 1992, 32 percent. Figure 1. Comparison of the frequency of tuskless females by age cohort Which of the following best describes the process responsible for the change in the percent of tuskless female elephants in the Gorongosa National Park population shown in Figure 1?