PSAT Reading Question 645: Answer and Explanation

Question: 645

What is the primary function of lines 52–56 ("For the . . . ecosystem") in the first paragraph of Passage 2?

• A. To establish the narrator's scholarly authority in this field of study
• B. To state the principal argument of the passage
• C. To summarize a common understanding that is subsequently refuted
• D. To contrast the work of ecologists with those of biologists

Correct Answer: C

Explanation:

(C) The author immediately contradicts this statement in the following sentence. The general purpose of placing the sentence from lines 52–56 in the passage is to give a general summary of what many people think about this issue and then to use the entire passage to show why most people are incorrect about this topic. Choice (A) is incorrect because this text only indirectly establishes the author's authority. Choice (B) is not right because the thesis of the passage comes in the sentence that follows. Choice (D) is incorrect because ecologists and biologists are in agreement according to this sentence.