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by smagish » Sat Oct 20, 2012 8:36 am
Tektites, which may have been propelled to Earth from lunar volcanoes, are much
like the volcanic glass obsidian, but their chemical composition is different than
any terrestrial lava; they contain
far less water than obsidian does and none of its
characteristic microcrystals.
(A) is different than any terrestrial lava; they contain
(B) is different than any terrestrial lava's, containing
(C) is different from that of any terrestrial lava; they contain
(D) differs from any terrestrial lava in containing
(E) differs from that of any terrestrial lava's, containing

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by anuprajan5 » Sat Oct 20, 2012 8:57 am
The answer is C

(A) is different than any terrestrial lava; they contain - Comparisob is between chemical composition and lava. Also different than seems odd.

(B) is different than any terrestrial lava's, containing - Wordy

(C) is different from that of any terrestrial lava; they contain - Perfect
(D) differs from any terrestrial lava in containing - Comparison issue
(E) differs from that of any terrestrial lava's, containing - Redundant. that of any lava's

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by sanrisenew » Sun Oct 21, 2012 10:49 am
The last phrase "none of its characteristic microcrystals" is reffering to what?

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by anuprajan5 » Sun Oct 21, 2012 10:05 pm
Hi,

It refers back to obsidian because obsidian is the only singular noun that has a singular verb does, whereas tektites are a plural noun with the plural verb are

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by ihatemaths » Mon Oct 22, 2012 1:15 am
experts please explain the error in E not able to understand what's wrong with the option

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by Kasia@EconomistGMAT » Mon Oct 22, 2012 12:55 pm
Answer E is incorrect. The pronoun "that" replaces the phrase "chemical composition." The use of the form "lava's" suggests that one more noun has been elided to make the sentence more concise and in a longer form without ellipsis the full expression would be "lava's composition." So the full, longer version of this sentence would be phrase in the following way:

Tektites, which may have been propelled to Earth from lunar volcanoes, are much
like the volcanic glass obsidian, but their chemical composition differs from the CHEMICAL COMPOSITION of any terrestrial lava's COMPOSITION, containing far less water than obsidian does and none of its characteristic microcrystals.

Thus the use of the form "lava's" is incorrect.
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