The passage is basically trying to arrive at conclusion with respect to hypotheses about the state of the Earth's crust in the past. The assumption here is that both laboratory grown fullerenes and naturally occurring fullerenes are similar and, since laboratory synthesis of fullerenes requires distinctive conditions of temperature and pressure, geologists can assume that similar conditions must be needed for naturally occurring fullerenes to grow. Based on this principle the passage suggests that geologists should evaluate their hypotheses.

One way to undermine this argument is to undermine the very basic assumption that both laboratory grown fullerenes and naturally occurring fullerenes are similar. If both laboratory grown fullerenes and naturally occurring fullerenes are different, then it possible that both require different conditions to grow and if this is true, then the principle on which the passage suggests the geologists should test the hypotheses doesn't seem helpful.

Option D does the same job I just explained above. D says that the naturally occurring fullerenes are arranged in a previously unknown crystalline structure. So we can safely infer that both laboratory grown fullerenes and naturally grown fullerenes are different because if they were same, then geologists would have been aware of this unknown crystalline structure.

Hope that helps..

Hi,

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

...Hardik's explanation was awesome.

@gmatperfect: it would benefit you if you used the search function prior to posting--that way you may encounter solutions to your problems, and you may not even have to post. It would also benefit BTG, helping us keep things organized around here!

Very good explanation.
Thanks...

Everybody got really hyped about longevity experiments concerning C60 fullerene dispersed in olive oil but to be honest, main focus of today's practical application of this material is industrial area. Fullerenes are perfect for different kinds of enhancing coating, lubricants, electrical conductors etc. Its awesome that the industry is growing. For example check out this site. Looking forward to future medical development as well though.