Re: Although fullerenes - spherical molecules made entirely of

Hi adg142000

I’m glad to help.

This question uses a very common flaw of reasoning:
Fact: X leads to A
Fact: Y leads to A
Conclusion: X = Y.
This is wrong. Same ending does not mean same beginning.

Back to the question.

Fact: fullerenes - spherical molecules made entirely of carbon - were first found in the laboratory
Fact: fullerenes also have been found in nature, formed in fissures of the rare mineral shungite.
Fact: laboratory synthesis of fullerenes requires distinctive conditions of temperature and pressure
Conclusion: We could know about the state of the Earth's crust at the time these naturally occurring fullerenes were formed.

Assumption: the previous structure of fullereness formed in lab and that of fullererness formed in nature is the same.

What if scientists synthesize fullerness from substance X. But in nature fullerness was actually formed from substance Y ==> We cannot say the condition of the Earth’s crust at the time fullerness naturally formed is the same as the condition of lab at the time fullerness synthesized artificially.

What D says:

D. The naturally occurring fullerenes are arranged in a previously unknown crystalline structure
D clearly says: we don't know what previous structure of fullererness formed naturally.
For example: The flow is: carbon 12 ==> carbon 14 ==> fullererness. Assume the lab synthesizes fullererness from carbon 12, but in nature, fullererness was formed from carbon 14 ==> cannot say the state of the Earth's crust at the time these naturally occurring fullerenes were formed is the same as the condition in lab.

Hence, D weakens the conclusion and is correct.

Hope it helps.