Hi,

I discussed this question right here: https://www.beatthegmat.com/gmat-prep-fu ... 47834.html

As it happens, this question was very recently discussed. Please use the search function before posting. You will benefit from reading solutions that have already been posted!

Hi gmatmillenium,

Aah, the Fullerenes problem again. This is a toughie. The argument claims that the discovery of naturally occuring fullerenes will reveal information th earth at the time the fullerenes were created. Since fullerenes are formed in the lab under specific conditions, the author makes his claim because he assumes that if fullerenes are found anywhere, it's because these specific conditions were present at the time of creation. In other words, if it takes 10,000 degrees to form Fullerenes in the lab, finding fullerenes in nature means (according to the argument) that when they were formed, earth's crust was 10,000 degrees.

To weaken the argument, we can simply say that the fullerenes found in nature are a different type of fullerenes; one whose conditions for creation are unknown. If this were the case, then our knowledge of how fullerenes are formed in the lab would be useless to learn about the earth's crust at the time the natural fullerenes were formed. This is what D does, so D is the correct answer.

A much more detailed discussion of the question can be found at GMATPrep Question 2028. You can practice timed drills with similar questions by setting topic='CR Weaken' and difficulty='700+' in the Drill Generator.

-Patrick

What's the conclusion of the argument?

That we can use the natural fullerenes to learn about the earth's crust.

What the assumption?

Natural fullerenes = earth's crust. The argument assumes that there is a connection between these two things.

Predict the answer:

Since we're trying to weaken the conclusion, we need an answer choice that breaks the link between the the natural fullerenes and the earth's crust, that says we won't be able to use the natural fullerenes to learn about the earth's crust.

Answer choice is D is correct because it says that the natural fullerenes are of an unknown structure; hence, we might not be able to use them to learn about the earth's crust.