Zoologists warn of an imminent surge in the number of bird species tha

OFFICIAL EXPLANATION

The conclusion of the argument is that the rate of extinction of bird species will not surge in this century. Evidence from native North American raptors (birds of prey) is cited: namely, that even though several such species nearly vanished between 1900 and 1970, the populations of these birds have since rebounded. We are asked to select a question which would, when answered, provide information that would help us evaluate this claim.

(A) This answer choice inquires about the introduction of non-native raptors. However, the argument cites as evidence the resurgence in native raptor populations. Thus, this question does not shed light on the relevance of the evidence.

(B) CORRECT. This question points to an unwarranted assumption on the author's part. The author assumes that the rebound in native North American raptor populations since 1970 was not due to any special effort to save these species. If special efforts have been made to save these raptor species, then one might not be able to generalize this evidence to other bird species or to make predictions about population trends in the next century, using this evidence.

(C) This question is irrelevant: the argument does not depend in any way on the experience of the zoologists. It hinges instead on the trend in raptor populations that the author uses to justify his or her point.

(D) This question is irrelevant. Note that the given evidence states that "local populations of these raptors have rebounded." Thus, population increases of native North American raptors outside of North America are not pertinent.

(E) This question is irrelevant: the argument does not depend in any way on the number of acres of woodland set aside as bird refuges.