+HOT Competition 4 Sep/8AM: Presolar grains, which may be older than

Presolar grains, which may be older than our solar system, are much like ordinary meteorite fragments, but their chemical composition is different than any typical extraterrestrial mineral; they contain trace amounts of helium and neon and slightly less silicon carbide than the average meteor does.

(A) is different than any typical extraterrestrial mineral; they contain

“different than any” is unidiomatic

(B) is different than any typical extraterrestrial mineral’s, containing

“different than any” is unidiomatic

(C) is different from that of any typical extraterrestrial mineral; they contain

Correct: “different from” is correct and “that of” also correctly refers to “composition”. Semicolon used correctly to start a new clause.

(D) differs from any typical extraterrestrial mineral in containing

Incorrect comparison: composition is compared with minerals, not with their composition
“in containing” changes the intended meaning.

(E) differs from that of any typical extraterrestrial mineral, containing

“containing” refers to the closest action “are different” and thus makes the sentence illogical because now it means that A is different by containing X. hence out.


Hence C

Presolar grains, which may be older than our solar system, are much like ordinary meteorite fragments, but their chemical composition is different than any typical extraterrestrial mineral; they contain trace amounts of helium and neon and slightly less silicon carbide than the average meteor does.

(A) is different than any typical extraterrestrial mineral; they contain --> Should use 'different from' something instead of 'different than'.
(B) is different than any typical extraterrestrial mineral’s, containing --> Should use 'different from' something instead of 'different than'.
(C) is different from that of any typical extraterrestrial mineral; they contain --> Correct comparison by compare composition.
(D) differs from any typical extraterrestrial mineral in containing --> Wrong comparison between composition and mineral.
(E) differs from that of any typical extraterrestrial mineral, containing --> We need verb here because the non-underlined part has the verb, does.

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Experts Global Explanation:

Comparisons + Idioms + Modifiers

Please remember, in a “noun + comma + phrase” construction, the phrase must correctly modify the noun; this is one of the most frequently tested concepts on GMAT sentence correction.

A. This answer choice incorrectly compares the “chemical composition” of presolar grains to the noun “any typical extraterrestrial mineral” rather than to the chemical composition of the said mineral. Additionally, Option A utilizes the unidiomatic construction “different than” rather than the proper construction, “different from”.

B. This answer choice repeats the idiom-related error seen in Option A, incorrectly using the unidiomatic construction “different than” rather than the proper construction, “different from”. Furthermore, Option B features a modifier error; the phrase “containing trace amounts of…” incorrectly modifies the possessive noun “any typical extraterrestrial mineral’s” rather than the noun “presolar grains”, implying that the chemical composition of any typical extraterrestrial mineral “contains trace amounts of helium and neon and slightly less silicon carbide than the average meteor does”.

C. This answer choice correctly compares the chemical composition of presolar grains to the composition of “any typical extraterrestrial mineral”, maintains proper idiom use, and maintains proper modifier use to preserve the intended meaning of the sentence.

D. This answer choice repeats the comparison error seen in Option A, comparing the “chemical composition” of presolar grains to the noun “any typical extraterrestrial mineral” rather than to the chemical composition of the said mineral.

E. This answer choice features a modifier error; it incorrectly uses the phrase “containing trace amounts of…” to modify the pronoun phrase “that of any typical extraterrestrial mineral” rather than the noun “presolar grains”

C is the best answer choice.

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