Bunuel wrote:
Dolphins can swim at high speeds and achieve high acceleration in the water. In 1936, Sir James Gray calculated the force dolphins should be able to exert based on their physiology. He concluded that the propulsive force they were able to exert was not enough to explain how fast they swim and accelerate. In the 2000s, experimenters used special computer-enhanced measurements of the water in which dolphins were swimming. Through mathematical modeling, they were able to measure the force dolphins exert with their tails. As it turns out, dolphins exert considerably more force with their tails than Sir James Gray or anybody else ever expected. Therefore, the force exerted by their tails easily explains how fast they swim and accelerate.
In the argument, the two portions in boldface play which of the following roles?
(A) This first is a piece of evidence supporting the main conclusion; the second is the main conclusion.
(B) The first is a false conclusion based on an incorrect premise; the second is the revised conclusion drawn from the corrected premise.
(C) The first is an opinion the author seeks to refute; the second is the opinion the author supports.
(D) The first is a prediction that, if accurate, would provide support for the main conclusion of the argument; the second is the main conclusion.
(E) The first is a generally held assumption; the second is a conclusion that violates that assumption.
Magoosh Official Explanation:
In this passage, the first bold statement is an incorrect conclusion. Sir James Grey knew at the time that it was incorrect: he knew that his current understanding of the physiology of dolphins could not explain how fast they move. It was the best science could do, given the evidence available at the time. The second bold statement is the correct conclusion, which resolves the paradox and explains everything in terms of our modern measurements.
(B) is the credited answer. The first is false, and it was based on what we now realize was an incorrect assumption. The second is the true statement based on correct evidence.
(A) is wrong: Sir James Grey's conclusion is not a piece of evidence, and it does not support the conclusion.
(C) is wrong: neither one of these are "opinions." Rather, both of them are scientific deductions.
(D) is wrong: there is no reason to specific that something about the first one "if accurate." We know the first statement is false: in fact, Sir James Grey knew it had to be false.
(E) is wrong; the first statement is not generally held and it is not an assumption.