Sound can travel through water for enormous distances, prevented from

Yes, option (C) has an absolute phrase (underlined)

Sound can travel through water for enormous distances, its acoustic energy prevented from dissipating by boundaries in the ocean created by water layers of different temperatures and densities.

Thanks a lot again for the prompt reply. You rock

Hi AndrewN - loved the way meaning was used to eliminate betwen E vs C

Just curious, can you use meaning to eliminate D ?

I thought D made sense from a meaning perspective also because

• Thought it was possible for boundaries to be responsible for the act of accoustic energy being dissipated specifically
  

Given this possibility perhaps was taking place (note - i am not a science major) -- i could not cross off D vs C, based on meaning.

I guessed between C and D

Hello, jabhatta2. Thank you for the kind words. How about we take a look at answer choices (C) and (D) side by side in the context of the sentence?


You can see that there are two differences between the two options. Although the first split has the potential to lead to more than one interpretation, I would call each an issue of diction—the manner in which an idea is expressed in written form—rather than one of meaning. Both dissipating and being dissipated are gerunds serving as the object of the preposition from. In the former iteration, the energy itself is said to be doing something, dissipating, while in the latter, I cannot dismiss the interpretation, on grammar alone, that the energy could purportedly be dissipated via the boundaries that follow the underlined portion. Consider:

a) [something] prevented from being dissipated — i.e. it would dissipate on its own if not for some unnamed obstacle (the emphasis is on prevented)

b) [something] prevented from being dissipated — i.e. it would not dissipate on its own, but would require some unnamed agent to facilitate its dissipation (the emphasis is on being)

I think a more compelling case can be made semantically for the first interpretation. Something that prevents is not understood at the same time to be requisite to allowing a process to unfold. (Even a catalyst contributes to a reaction.) As such, I would say that ambiguity of meaning is not an issue here: dissipating is simply a better, clearer way of saying what needs to be said than being dissipated.

Now, in terms of the second split, by follows a patent passive construct: [verb-ed] + by + noun; as a result of is typically used to preface a noun phrase, one that explains a process of some sort. As a result of boundaries does not make sense—and this sort of construct, as a result + noun/pronoun, is often used in incorrect answer choices—but if we first encountered a description of what those boundaries were doing, such usage would be more appropriate:

As a result of the viscosity of seawater, in combination with other factors that can create underwater boundaries, the acoustic energy of sound is prevented from dissipating.

I am not saying that the above sentence would be the one and only way of expressing the idea, but it is a passable sentence.

In short, I would disfavor (D) because (C) conveys the vital meaning of the sentence in a clear and concise way. Thank you for thinking to follow up with me on this one. Good luck with your studies.

- Andrew

Hi Andrew,
I got the meaning of C and understand why its wrong.
According to your explanation In then end, do boundries help sound's acoustic energy from dissipating?
or boundries act as a hurdle for sound and as a result its hard for sound to go through it?
so its energy is prevented from dissipating by boundries of ocean.
In other words "by boundries..." is modfying dissipating or prevented in C? I think both have a slightly different meaning?
Is it true?

Hello, dcoolguy. A boundary is, by definition, a barrier of some sort, so within the sentence at hand, we understand that water layers are acting as a collective boundary that keeps sound more "intact" than such energy waves would be on their own. Thus, these boundaries aid in the transfer of sound over enormous distances through seawater. (Without the boundaries, the sound would dissipate.)

Thank you for following up.

- Andrew

Hi GMATGuruNY - while i agree (C) is the answer, what is the absolute modifier in (C) modifying ? Is the absolute phrase, modfiying



Absolute modifiers i think modify clauses but the subect of the clause is the closest noun i thought (which would be - distances)

Typical construction of an absolute phrase:
COMMA + POSSESSIVE + NOUN or NOUN PHRASE + MODIFIER(S)
Generally, the possessive and noun will refer to the preceding subject, while the entire phrase plays an adverbial role, providing context for the preceding action.
In most cases, an absolute phrase will appear at the END of an SC.

OA: Sound can travel through water for enormous distances, its acoustic energy prevented from dissipating by boundaries in the ocean.
Here:
The portion in blue is an absolute phrase.
its acoustic energy (possessive + noun phrase) refers to sound (the preceding subject).
The entire absolute phrase provides context for the preceding action -- can travel -- expressing why sound CAN TRAVEL for enormous distances.

In this question, answer C cannot be correct as it will end up connecting two independent clauses by only a comma - which is incorrect. How come it is the right answer?

Notice that, in the (C) version, "prevented" does not name an action taken by the acoustic energy. Rather, "prevented from dissipating" describes the acoustic energy. So, there's no verb in the structure that follows the comma.

So, what follows the comma in the (C) version is not a clause. It's a type of modifying phrase called an absolute phrase

As MartyTargetTestPrep suggests, prevented is acting as a "past participle" and not as a "simple past tense verb" in option C.

p.s. Our book EducationAisle Sentence Correction Nirvana discusses framework to distinguish between Simple Past Tense verb and Past participle, its application and examples in significant detail. If you or someone is interested, PM me your email-id; I can mail the corresponding section.

Hi, can someone explain what is the problem with option D? I understand that "as a result of" sounds wordy but can someone give me a better reason?

Hello sv2023,

We hope this finds you well.

To answer your query, the only flaw in Option D is, indeed, its wordiness; the use of the phrase "prevented from being dissipated as a result of" leads to awkwardness and redundancy.

We hope this helps.
All the best!
Experts' Global Team

Hi sv2023,

Apart from wordiness/awkwardness, as a result of also leads to loss of meaning clarity. That is, by does a much better job of telling us that what prevents acoustic energy from dissipating is boundaries.

GMATGuruNY - you said COMMA + Verb'ed ALWAYS modify the closest noun ?

Is there a reason why Comma + Verb'ing modify the subject and the clause WHEREAS COMMA + Verb'ed does not follow that same pattern ?

What is the reason for this difference ?

I thought COMMA + Verb'ed and Comma + Verb'ing were both adverbial modifers at the end of the day

This statement is not quite correct.
Whereas COMMA + VERBing plays an important adverbial role, COMMA + VERbed generally does not.

COMMA + VERBed functions primarily as an ADJECTIVE modifying the preceding noun or noun phrase.
An incorrect answer choice in the OG20:
Many of the images date from the time of the Kushan Empire, fashioned from the spotted sandstone of Mathura.
The OG's explanation:
Placement of the modifier fashioned suggests that the Empire (the closest noun), not the images, was fashioned out of these materials.
Any adverbial role played by COMMA + VERBed will be quite limited.
Here, the modifier fashioned tells us nothing about the preceding action (how the images DATE).

When it follows a clause, however, COMMA + VERBing serves both as an ADJECTIVE (modifying the preceding subject) and as an ADVERB (providing context for the preceding verb).
An OA in the OG12:
Animal-hide shields were essential items of military equipment, protecting warriors against enemy arrows.
Here, COMMA + protecting serves both as an ADJECTIVE modifying the preceding subject shields (since the SHIELDS perform the act of PROTECTING) and as an ADVERB modifying the preceding verb were (expressing WHY the shields WERE essential).

In short, the two modifiers function differently.
Whereas COMMA + VERBed typically modifies the preceding noun or noun phrase, COMMA + VERBing after a clause modifies the preceding subject and verb.

The issue is not wordiness but meaning.
by and as a result of convey different meanings.

Correct: Mary was promoted by her boss.
Incorrect: Mary was promoted as a result of her boss.
Here, the noun phrase in blue performs the preceding action -- the boss promoted Mary -- so we use by rather than as a result of.

Incorrect: Mary was laid off by the recession.
Correct: Mary was laid off as a result of the recession.
Here, the noun in blue does NOT perform the preceding action -- the recession did not lay Mary off -- so we use as a result of rather than by.

OA for the SC above:
its acoustic energy prevented from dissipating by boundaries in the ocean.
Here, the noun phrase in blue performs the preceding action -- the boundaries prevent the energy from dissipating -- so we use by rather than as a result of.

Also:
Correctly used, as a result of should generally refer to the OUTCOME of an action, event, change, etc.
as a result of THE NEW LAW
as a result of THE RECESSION
as a result of THE INCREASE
In D, boundaries do not constitute an action, event or change, so the use of as result of seems illogical.