GMAT CLUB OLYMPICS: One of the most intriguing topics for geologists h

Explanation:

Strategy: Determining the main conclusion of the argument and finding the relation of the boldfaced portions with this conclusion

Logic: The argument explores the consequences of an event. The argument mentions, as the first boldface states, that an asteroid crashed at a particular location 66 million years ago. The argument subsequently mentions that the impact caused mass extinction because the crash resulted in extreme global cooling. The argument goes on to mention, as the second boldface states, that other similar crashes have happened but not caused mass extinction, and offers an explanation to justify the lack of mass extinction in those crashes. Overall, the main conclusion is that the impact of the asteroid crash caused mass extinction because the site of the crash had the right mix of volatile rocks, thus resulting in extreme global cooling. In the context of the main conclusion – the first boldface is the event whose consequences the argument assesses in the main conclusion; the second boldface is an observation that the argument uses to establish the main conclusion.

Main conclusion (implicit): The impact of the asteroid crash caused mass extinction because the site of the crash had the right mix of volatile rocks, thus resulting in extreme global cooling.

Broad expectation from the correct answer choice:
The first boldface is the event whose consequences the argument assesses in the implicitmain conclusion.
The second boldface is an observation that the argument uses to establish the implicitmain conclusion.

A.
Merit(s):
The second boldface states factual events; therefore, it is broadly correct to state that the second boldface is an “evidence”.

Demerit(s):
The first boldface is a factual event whose consequences the argument assesses; the argument does not use the first boldface for validation of an idea; therefore, it is largely incorrect to state that the first boldface is an “evidence”.
The argument assesses the consequences of the first boldface; the first boldface does not pass any judgment on the conclusion; therefore, it is incorrect to state that the first boldface “challenges the position that the argument seeks to establish”.
The argument uses the second boldface to establish the implicitmain conclusion; so, the second boldface supports the argument’s position; therefore, it is incorrect to state that the second boldface “challenges the position that the argument seeks to establish”.

Because this answer choice does not correctly highlight the roles played by the two portions in boldface, this answer choice is incorrect.

B.
Merit(s):
The second boldface states factual events; therefore, it is broadly correct to state that the second boldface is an “evidence”.
The argument uses the second boldface to establish the implicitmain conclusion; therefore, it is correct to state that the second boldface “supports the position that the argument seeks to establish”.

Demerit(s):
The first boldface is a factual event whose consequences the argument assesses; the argument does not use the first boldface for validation of an idea; therefore, it is largely incorrect to state that the first boldface is an “evidence”.
The argument assesses the consequences of the first boldface; the first boldface does not pass any judgment on the conclusion; therefore, it is incorrect to state that the first boldface “supports the position that the argument seeks to establish”.

Because this answer choice does not correctly highlight the roles played by the two portions in boldface, this answer choice is incorrect.

C.
Merit(s):
The first boldface is a factual event; therefore, it is correct to state that the first boldface is a “circumstance”.
The argument assesses the consequences of the first boldface to establish the implicitmain conclusion; therefore, it is correct to state that the “implications of the first boldface are evaluated in the argument”.

Demerit(s):
The argument uses the second boldface to establish the implicitmain conclusion andthe second boldface itself is not the main conclusion; therefore, it is incorrect to state that the second boldface is the “main conclusion of the argument”.

Because this answer choice does not correctly highlight the roles played by the two portions in boldface, this answer choice is incorrect.

D.
Merit(s):
The first boldface is a factual event; therefore, it is broadly correct to state that the first boldface is a “finding”.
The second boldface is an observation that the argument uses to establish the implicitmain conclusion; therefore, it is correct to state that the second boldface is a “consideration”.

Demerit(s):
The argument assesses the consequences of the first boldface and does not assess the correctness of the first boldface; therefore, it is incorrect to state that the “accuracy of the first boldface is evaluated in the argument”.
The two boldfaces are two independent events and pass no judgment on each other; therefore, it is incorrect to state that second boldface “establishes that the finding in the first boldface is accurate”.

Because this answer choice does not correctly highlight the roles played by the two portions in boldface, this answer choice is incorrect.

E.
Merit(s):
The first boldface is a factual event; therefore, it is broadly correct to state that the first boldface is a “finding”.
The argument assesses the consequences of the first boldface to establish the implicitmain conclusion; therefore, it is correct to state that the “implications of the first boldface are evaluated in the argument”.
The second boldface is an observation that the argument gives careful thought to and uses to establish the implicitmain conclusion; therefore, it is correct to state that the second boldface is a “consideration”.
The argument uses the second boldface to establish the implicitmain conclusion; therefore, it is correct to state that the second boldface “supports the position that the argument seeks to establish”.

Demerit(s):
None

Because this answer choice correctly highlights the roles played by the two portions in boldface, this answer choice is correct.

E is the best answer choice.