Dear Friends,
Here is a detailed explanation to this question-
Economist wrote:
Sound can travel through water for enormous distances,
prevented from dissipating its acoustic energy as a result of boundaries in the ocean created by water layers of different temperatures and densities.
(A) prevented from dissipating its acoustic energy as a result of
(B) prevented from having its acoustic energy dissipated by
(C) its acoustic energy prevented from dissipating by
(D) its acoustic energy prevented from being dissipated as a result of
(E) preventing its acoustic energy from dissipating by
[spoiler=]
https://www.nytimes.com/1998/10/27/science/global-thermometer-imperiled-by-dispute.htmlSound can travel through water for enormous distances,
prevented from dissipating its acoustic energy by boundaries in the ocean created by water layers of differing temperatures and densities. In the final version of the experiment, loudspeakers were installed at two sites: one off the northwest coast of Hawaii's Big Island, and the other near Pioneer Seamount, a volcanic island in the Pacific Ocean 55 miles from San Francisco. The times of arrival of the sound at thousands of underwater microphones spanning the Pacific Ocean were then recorded and interpreted as water temperatures.
Meaning is crucial to solving this problem:Understanding the intended meaning is key to solving this question; the intended meaning of this sentence is that sound can travel through water for enormous distances because its acoustic energy is prevented from dissipating by boundaries in the ocean created by water layers of different temperatures and densities.
Concepts tested here: Meaning + Modifiers + Verb Forms• In the “phrase + comma + noun” and “noun + comma + phrase” constructions, the phrase must correctly modify the noun; this is one of the most frequently tested concepts on GMAT sentence correction.
• The introduction of the present participle ("verb+ing"- “preventing” in this case) after comma generally leads to a cause-effect relationship.
A: This answer choice incorrectly modifies "prevented from dissipating its acoustic energy...", leading to an incoherent meaning; the intended meaning is that sound can travel through water for enormous distances because its acoustic energy is prevented from dissipating by boundaries in the ocean created by water layers of different temperatures and densities; remember, in the “phrase + comma + noun” and “noun + comma + phrase” constructions, the phrase must correctly modify the noun.
B: This answer choice incorrectly modifies "prevented from having its acoustic energy...", leading to an incoherent meaning; the intended meaning is that sound can travel through water for enormous distances because its acoustic energy is prevented from dissipating by boundaries in the ocean created by water layers of different temperatures and densities; remember, in the “phrase + comma + noun” and “noun + comma + phrase” constructions, the phrase must correctly modify the noun. Further, Option B uses the passive voice construction "prevented from having its acoustic energy dissipated", leading to awkwardness and redundancy.
C: Correct. This answer choice avoids the modifer error seen in Options A and B and the verb form error seen in Option E, as it uses the phrase "its acoustic energy prevented from dissipating", correctly modifying the preceding clause to convey the intended meaning - that sound can travel through water for enormous distances because its acoustic energy is prevented from dissipating by boundaries in the ocean created by water layers of different temperatures and densities. Further, Option C is free of any awkwardness or redundancy.
D: This answer choice uses the needlessly wordy phrase "prevented from being dissipated as a result of", leading to awkwardness and redundancy.
E: This answer choice alters the meaning of the sentence through the phrase "preventing its acoustic energy from dissipating"; the use of the "comma + present participle ("verb+ing" - "preventing" in this sentence) incorrectly implies that sound can travel through water for enormous distances and as a result, sound prevents its acoustic energy from dissipating due to boundaries in the ocean created by water layers of different temperatures and densities; the intended meaning is that sound can travel through water for enormous distances because its acoustic energy is prevented from dissipating by boundaries in the ocean created by water layers of different temperatures and densities; remember, the introduction of the present participle ("verb+ing"- “preventing” in this case) after comma generally leads to a cause-effect relationship.
Hence, C is the best answer choice.To understand the concept of "Phrase Comma Subject" and "Subject Comma Phrase" on GMAT, you may want to watch the following video (~1minute):
To understand the concept of "Comma + Present Participle for Cause-Effect Relationship" on GMAT, you may want to watch the following video (~3 minutes):
All the best!
Experts' Global Team
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