With the private space industry at the early stages of launch revoluti

some times i study question outside og or gmatprep source.
this question is strange. i want to say something

choice A and E contain "rocket" without "a,the" . they are wrong.

if we read choice b,c and d, dont be confused by many phrases changing their places in the sentence. intead, just focus on what is the main core idea.

to get the core idea of sentence, ask ourself. which do which.

I answer this question after reading many phrase and understand nothing. my answer is

study effect of plume

is main core. and this is most logic.

from this point. i can go to the correct answer.

Since the rocket launches is going to increase , hence as per logic, the study should be of the affect of plumes of exhaust of a number of rockets, on the Atmosphere(stratosphere and ozonosphere) . Study cannot be constituted of a single rocket exhaust

Eliminating all other options leaving B as the answer

I dont understand how B is the correct choice .
"their" in B can refer to "rockets" or can refer to "plumes of exhaust".

Where am i going wrong , can someone explain ?
Why A is wrong here?

TIA

Hi Harshjha001,

One way to take option A out is to focus on "rocket leaves". Normally, we'd want "a rocket leaves" or "rockets leave".

1. ... the plume of exhaust that rocket leaves...
vs.
2. ... the plume of exhaust that a rocket leaves...
or
3. ... the plume of exhaust that rockets leave... (this one needs a plural pronoun)

AjiteshArun Can you please throw some light on how these ICs are co-joined by just hyphens. Studying starts with a capital S, I took this construction to be awkward. Can you share some insight into it. Thank you in advance.

Hi nikhilongc,

Good catch. There really should be a pair of dashes there. Think of a pair of em dashes as a pause or break in the sentence that allows us to introduce the kind of thought we could use a pair of brackets for. Also, dashes should normally be closed (that's why we often see a pair of dashes), as in (1) below, but, of course, we can't do that if the element that the dash introduces ends the sentence (2). Keep in mind that we cannot use any commas next to dashes.

1. AB—XY—CD.

2. AB—XY.

3. AB—XY—.

The sentence the correct option leads to is like (1): AB—XY—CD. Now, whatever that XY may be, it won't affect the structure of the rest of the sentence. So (1) is like (4) below:

4. AB (XY) CD.

This is one way to see that the XY element is not joined to CD in any way. In fact, it is set off from CD. The core of the sentence is AB, CD (the comma is removed when dashes are introduced).

You could also try this official question instead.

Hi AjiteshArun,

I have a three doubts.
A. it has become imperative to study the effects of the plume of exhaust that rocket leaves in its wake on the stratosphere and the Ozone layer.
E. it has become imperative to study how the plumes of exhaust that rocket leaves in its wake affects the stratosphere and ozone layer .
1) In option A and E is it a placeholder pronoun or does it lead to an antecedent error along with the rocket leaves error?

C. The plume of exhaust left by a rocket in its wake has to be studied for its effect on the stratosphere and Ozone layer.
2) in option C doesn't the its lead to a pronoun antecedent ambiguity error. The first one refers to rocket and second one to the plume?

B. Studying the effects on the stratosphere and Ozone layer caused by the plumes of exhaust left by rockets in their wake has become imperative.
3) why did the studying start with a capital S?

Regards
Aswin Dinesh

Hi Aswin12,

1. Yes, this is a placeholder it. This type of it is used to shift an awkward subject to the right (which makes the sentence easier to read). We can say that the it ~refers to to study the effects of the plume of exhaust. If we did not use an it as the subject, we'd end up with something like to study the effects... has become imperative, which is quite awkward.

2. Good catch. Yes, technically, the pronoun is ambiguous, but pronoun ambiguity isn't an absolute error. So if I see multiple pronouns referring to different nouns I still hold on to that option (see this question, similar, though not the same). Just to be clear, this is definitely a red flag. It's just that I don't see it as an absolute error.

3. If I had to guess, I'd say that it's a typo. I'll let the mods know, and they can take a call on this. Until then, I'll continue trying to gently steer people to this official question.

Isn't exhaust and left redundant since exhaust is always leaving and not entering

Posted from my mobile device

Hello Vicky1811,

We hope this finds you well.

To answer your query, it is important to remember that redundancy is the least critical factor in GMAT sentence correction; the question of redundancy should only be taken into account when you need to select between two otherwise error-free answer choices.

Thus, even if the use of "left" is a bit redundant here, it is not a matter of concern.

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

Hi

Can someone explain B) vs C) please?
Is it because of meaning? Studying the plumes vs studying the effects?

Thanks,
-AC.