PSAT Reading Question 646: Answer and Explanation

Question: 646

Which of the following situations would be most similar to that discussed in lines 66–73 ("Having . . . birds")?

• A. Large whale species consume krill at higher latitudes.
• B. The male gorilla does not help with infants but does help defend against predators.
• C. Oxpecker birds eat predatory insects off the backs of zebras.
• D. Humans consume crabs they fish from the ocean.

Correct Answer: C

Explanation:

(C) Lines 66–73 describe a "mutualist" relationship, in which the species help one another. This is most similar to the oxpecker birds eating the predatory insects off the backs of zebras. The oxpeckers are gaining food, and the zebras are being cleaned. Choices (A) and (D) involve relationships beneficial to only one of the species. Choice (B) does not establish a reciprocal relationship with another species.