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Here is a detailed explanation to this question-
elevinty wrote:
Sixty-five million years ago, according to some scientists, an asteroid bigger than Mount Everest slammed into North America, which, causing plant and animal extinctions, marks the end of the geologic era known as the Cretaceous Period.
(A) which, causing plant and animal extinctions, marks
(B) which caused the plant and animal extinctions marking
(C) and causing plant and animal extinctions that mark
(D) an event that caused plant and animal extinctions, and it marks
(E) an event that caused the plant and animal extinctions that mark
Meaning is crucial to solving this problem:Understanding the intended meaning is key to solving this question; the intended meaning of the crucial part of this sentence is that an asteroid bigger than Mount Everest slammed into North America, and the asteroid doing so caused the plant and animal extinctions that mark the end of the Cretaceous Period.
Concepts tested here: Meaning + Modifiers + Tenses + Grammatical Construction• "who/whose/whom/which/where", when preceded by a comma, refer to the noun just before the comma.
• Information vital to the core meaning of the sentence cannot be placed between commas.
• Information that is permanent in nature is best conveyed through the simple present tense.
• The simple past tense is used to refer to actions that concluded in the past.
• The simple present continuous tense is used refer to actions that are currently ongoing and continuous in nature.
• Present participles ("verb+ing" – “marking” in this sentence) are used to modify nouns, refer to ongoing events in any time period, and (when preceded by a comma) express cause-effect relationships.
A: This answer choice incorrectly refers to "North America" with "which...marks the end of the geologic era known as the Cretaceous Period", illogically implying that
North America marks the end of the Cretaceous Period; the intended meaning is that
the plant and animal extinctions caused by the asteroid slamming into North America mark the end of the Cretaceous Period; please remember, "who/whose/whom/which/where", when preceded by a comma, refer to the noun just before the comma. Further, Option A incorrectly places information that is vital to the core meaning of the sentence - that the asteroid slamming into North America caused plant and animal extinctions - between two commas; please remember, information vital to the core meaning of the sentence cannot be placed between commas.
B: This answer choice incorrectly refers to "North America" with "which caused the...the Cretaceous Period", illogically implying that
North America caused the plant and animal extinctions that mark the end of the Cretaceous Period; the intended meaning is that the
action of the asteroid slamming into North America caused the plant and animal extinctions that mark the end of the Cretaceous Period; please remember, "who/whose/whom/which/where", when preceded by a comma, refer to the noun just before the comma. Further, Option B incorrectly uses the present participle "marking" to refer to information that is permanent in nature; please remember, information that is permanent in nature is best conveyed through the simple present tense, and present participles ("verb+ing" – “marking” in this sentence) are used to modify nouns, refer to ongoing events in any time period, and (when preceded by a comma) express cause-effect relationships.
C: This answer choice alters the meaning of the sentence through the phrase "and causing plant and animal extinctions"; the construction of this phrase incorrectly implies that the asteroid slammed into North America and
as a separate action caused plant and animal extinctions; the intended meaning is that the asteroid slammed into North America and, and
it doing so caused plant and animal extinctions. Further, Option C incorrectly uses the simple present continuous tense verb "causing" to refer to an event that concluded in the past; please remember, the simple past tense is used to refer to actions that concluded in the past, and the simple present continuous tense is used refer to actions that are currently ongoing and continuous in nature.
D: This answer choice alters the meaning of the sentence through the phrase "and it marks the end of the geologic era known as the Cretaceous Period"; the construction of this phrase incorrectly implies that
the asteroid marks the end of the Cretaceous Period; the intended meaning is that
the plant and animal extinctions caused by the asteroid slamming into North America mark the end of the Cretaceous Period.
E: Correct. This answer choice uses the phrase "an event that caused the plant and animal extinctions that mark"; this phrase refers to the action of the asteroid slamming into North America, conveying the intended meaning - that the action of the asteroid slamming into North America caused the plant and animal extinctions that mark the end of the Cretaceous Period. Further, Option E correctly uses the simple past tense verb "caused" to refer to an event that concluded in the past. Moreover, Option E correctly uses the simple present tense verb "mark" to refer to information that is permanent in nature. Additionally, Option E avoids the grammatical construction error seen in Option A, as it placed no information between commas.
Hence, E is the best answer choice.To understand the concept of "Simple Tenses" on GMAT, you may want to watch the following video (~1 minute):
To understand the concept of "Simple Continuous Tenses" on GMAT, you may want to watch the following video (~1 minute):
To understand the concept of "Extra Information Between Commas" on GMAT, you may want to watch the following video (~1 minute):
All the best!
Experts' Global Team
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