With the private space industry at the early stages of a launch revolu

Gmatprep998

Please clarify underlined portion. I believe the entire portion after the hyphenated part must be underlined

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Hi, the underlined portion is not marked correctly.

Pls help to check

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A) it has become imperative to study the effects of the plume of exhaust that a rocket leaves in its wake on the stratosphere and the ozone layer
this means that rockets leaves in its wake on stratosphere. However we need the following structure: the effects of plume of exhaust on stratosphere and ozone.

The 'empty it' as found in (A) has widely been recognized as grammatically correct by the GMAT, how can that be the basis for a complete answer choice elimination?

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Let’s first understand the question here: With the private space industry at the early stages of a launch revolution […] a study has become imperative. Now, what is this study on? It’s on the effects on the atmosphere.

Option A. it has become imperative to study the effects of the plume of exhaust that a rocket leaves in its wake on the stratosphere and the ozone layer.

Option A – This option is long and winding.
See this part, for instance: “the effects of the plume of exhaust that a rocket leaves in its wake on the stratosphere” – there are too many prepositional phrases in there making it weak.
Therefore A is not the best option. But we know that the underlined portion should clearly mention that the study is on the effects. So first, we can eliminate all the options that do not say this.

Option C says “the plume of exhaust … has to be studied” – not the intended meaning of the sentence. Therefore, eliminate it.

Option D says “the study of the plumes of exhaust” – eliminate this option.

Option E seems to be alright until you get to “affects”. With “exhaust” as the subject, the verb should be “affect” – eliminate this option.

We are now left with Option B. Let’s take a look at that.

Option B. studying the effects on the stratosphere and the ozone layer caused by the plumes of exhaust left by rockets in their wake has become imperative

We can agree that this is a more concise option. We can go with B here.



IMO, using “it has become imperative” right after the dash makes “with the private space industry…” a misplaced modifier. When a sentence starts with WITH, we need to pay attention to what comes next. This is why B is the best option and not A.

Hope this clears things up!

OE

Look for differences across the answer options to identify what is being tested in the sentence.

The options are differing in the construction used to suggest that a study is needed. Some options are saying “it has become imperative to study”, others are saying “studying has become imperative” and (C) removes the word “imperative” and simply says “has to be studied”

What has to be studied is also different in the sentences. Should we study the effects, the plumes or how plumes affect the ozone?

Finally, the options are different in how the underlined portion begins.

Step 2 of solving this GMAT Sentence Correction Question: Understanding the Sentence
Because many more rocket launches are likely in the future, the effects of the exhaust on the stratosphere have to be studied.

The effects of the plume on the stratosphere have to be studied. An option that suggests that the plume has to be studied would be incorrect. It might well be impossible to study the actual plume because to do so will require that it be contained and not dispersed in the atmosphere.

Step 3 of solving this GMAT Sentence Correction Question: Eliminating Options
Option (C) suggests that the plume has to be studied, when in fact, the effects on the stratosphere have to be studied.

Option (D) also suggests that the plume has to be studied – again, impossible. Option (D) also uses the singular verb “has” to refer to the two studies – of the plume and of the effect.

Option (E) does not have subject-verb agreement either. The option uses the singular verb “affects” to refer to the plural “plumes”. Moreover, both options (E) and (A) use the construction “it has become imperative”. In this construction, the pronoun “it” does not have a noun to reference and such a generic usage of the same is considered ambiguous.

Choice B is the correct answer.

Gmatprep998

Here how do we know that the “it” in option A is not a placeholder “it”? Placeholder “it” is used for this very cause no?

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I have a question in B

studying the effects on the stratosphere and the ozone layer caused by the plumes of exhaust left by rockets in their wake has become imperative

Isn't caused a participle there modifying ozone layer? That just doesn't make sense at all. Could you please clarify that point?

The verb+ed modifier without a comma describes/modifies a noun or a noun phrase that precedes it.
In this case, 'caused' modifies 'the effects on the stratosphere and the ozone layer'

Does that help?

I am confused, could you please explain what would this sentence mean :-

The weight of the discus used in the tournament.

Is used modifying noun + prep phrase and hence modifying the weight or its modifying the discus or is it ambiguous?

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