求助prep 01-1

michaelmay17

Although fullerenes--spherical molecules made entirely of carbon--were first found in the laboratory, they have since been found in nature, formed in fissures of the rare mineral shungite. Since laboratory synthesis of fullerenes requires distinctive conditions of temperature and pressure, this discovery should give geologists a test case for evaluating hypotheses about the state of the Earth's crust at the time these naturally occurring fullerenes were formed.
Which of the following, if true, most seriously undermines the argument?
(A) Confirming that the shungite genuinely contained fullerenes took careful experimentation.
(B) Some fullerenes have also been found on the remains of a small meteorite that collided with a spacecraft.
(C) The mineral shungite itself contains large amounts of carbon, from which the fullerenes apparently formed.
(D) The naturally occurring fullerenes are arranged in a previously unknown crystalline structure.
(E) Shungite itself is formed only under distinctive conditions
答案选的是D，然后ABCE不正确也能理解，但是还是不懂D怎么么削弱了？

sdcar2010

D is the answer.

1) Scientist synthesized a chemical called fullerenes.
2) Naturally occurring fullerenes were found in the mineral shungite.
3) Assumptions: 1) The synthesized fullerenes and the naturally ocurring fullerenes in shungite have the same structure.
2) If the same structure are found in two compounds, then the two compounds require the same conditions to form.  
4) Conclusion: The condition on earth when the mineral shungite was formed could be known.

Answer D says the structure for fullerene in synthetic form are different from that in natural form of shungite.  Hence, the assumption 1) is wrong.  So is the conclusion then.

michaelmay17

D is the answer.

1) Scientist synthesized a chemical called fullerenes.
2) Naturally occurring fullerenes were found in the mineral shungite.
3) Assumption: If same structure, then the chemical requires the same conditions to form
4) Conclusion: The condition on earth when the mineral shungite was formed could be known.

Answer D says the structures for fullerenes and the mineral shungite are different.  Hence, the assumption is wrong.  So is the conclusion then.

-- by 会员 sdcar2010 (2012/1/2 11:15:45)

谢谢你的详细分析啦~看懂了，再次感谢！