Here’s the answer to yesterday’s practice question:
Protective coloration is common among animals. Some animals are countershaded for camouflage. For example, the next time you pass a fish market, look at the specimens laid out for viewing. Fish are nearly always darker on top than on the bottom. The selective theory of camouflage has long been favored by some ichthyologists, who believed that countershading reduces the contrast between the shaded and unshaded areas of the body when the sun is shining on the fish from overhead and lessens its vulnerability to predators. However, the discovery that the Nile catfish is reverse-countershaded—that is, its dorsal (upper) surface is light and its ventral (lower) surface is dark—turned this theory on its head.
However, enterprising ichthyologists saved the selective theory of camouflage by observing that the Nile catfish swims upside down, primarily to feed from the surface of the water. Some ichthyologists speculate that the Nile catfish also swims upside down for protection.
The passage provides information on each of the following EXCEPT:
- etiology of countershading
- etiology of reverse-countershading
- feeding habits of countershaded fish
- selective theory of camouflage
- protective coloration of animals
(C) is the credited response.
This is a “hunt-and-peck” question.
(C) isn’t supported by the passage. Sentence 1 of Paragraph 2 mentions the feeding habits of the Nile catfish, which is an anomaly because it is reverse-countershaded. The feeding habits of countershaded fish are not discussed in this passage. Some readers may find this question challenging because it can
be difficult not to confuse countershading and reverse-countershading when reading the passage.
(A) is incorrect. Eliminating this response will be difficult for readers who don’t know the meaning of etiology, which means to describe or assign a cause. Sentences 5-6 of Paragraph 1 describe the etiology of countershading as a protective mechanism that helps fish escape predators.
(B) is incorrect. As is the case with (A), eliminating this response will be difficult for readers who don’t know the meaning of etiology. The final sentence of Paragraph 2 describes the etiology of reverse-countershading by suggesting that the Nile catfish also swims upside down for protection.
(D) is incorrect. The selective theory of camouflage is central to this passage. Sentences 5-6 in Paragraph 1 and Sentence 1 in Paragraph 2 deal with the selective theory of camouflage. In fact, one could argue that the primary purpose of the passage is to discuss the selective theory of camouflage. This response should be easy for readers to eliminate.
(E) is incorrect. Sentence 1 in Paragraph 1 states that protective coloration is common among animals. Sentence 2 in Paragraph 1 states that some animals are countershaded for camouflage. Some readers may have difficulty eliminating this response because they may believe, incorrectly, that fish aren’t animals, and most of the passage deals with protective coloration among fish.