Bunuel,
Could you correct the answer choice E? I eliminated E for exactly the reason mentioned by Johnny99.
Thanks!

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Fixed. Thank you.
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Anytime we have a helping verb, such as "may," it changes the form of the main verb. For example:

"Tim cooks dinner for his children every night, but only after they perform Les Miserables in its entirety."

Simple case here. "Tim" is singular, and the main verb, "cooks" is also singular. But watch what happens when we toss in a helping verb:

"Tim may cook dinner for his children..."

"Tim" is still singular, but because "cook" is paired with the helping verb "may" it takes a different form.

Same issue in (E): "Indoor air pollution may also impair."

Takeaway: when assessing subject-verb agreement, don't ignore helping verbs!

I hope that helps!
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Indoor air pollution can threaten the health of closely confined farm animals and the workers who tend them and perhaps as well impairs the quality of such farm products like eggs, poultry, and pork.

(A) perhaps as well impairs the quality of such farm products like
(B) perhaps as well impairs the quality of such farm products as
(C) perhaps also impairs the quality of such farm products like
(D) may also impair the quality of such farm products like
(E) may also impair the quality of such farm products as

Here in A and B 'perhaps as well' can't be parallel to 'can threaten' in the non - underlined part since meaning-wise 'perhaps' and 'as well' are opposite to each other. Also verb needs to be in base form due to the subjunctive nature of the sentence.

For others red highlighted text shows rejection of that option.
To mention examples 'such as' is required as is properly done in option E.
Correct answer E.

Question: Is 'perhaps also impair' in C correct(i opine that its correct)?
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Looking only at the parallelism in choice (C), we have, "Indoor air pollution (1) can threaten the health of closely confined farm animals and the workers who tend them and (2) perhaps also impairs the quality of..."

The singular verbs "can threaten" and "impairs" are parallel (we can ignore "perhaps also" while analyzing the parallelism). To see that more clearly, let's break up the list into two distinct pieces:

• (1) "Indoor air pollution can threaten the health of..."
• (2) "Indoor air pollution perhaps also impairs the quality of..."

These are both fine on their own, so the parallelism is okay in choice (C). But, again, choice (C) must be eliminated because of the "such... like".

I hope that helps!
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Threaten has to be parallel to impair .so,B is incorrect

GMATNinja What is the correct logic for eliminating option B ?

I am interested in it too.

I managed to come down to B and E and I choose E because it sounded better, but I would like to have a better explanation for eliminating B.

Please GMATNinja help us

Indoor air pollution can threaten the health of closely confined farm animals and the workers who tend them and perhaps as well impairs the quality of such farm products like eggs, poultry, and pork.

(A) perhaps as well impairs the quality of such farm products like
(B) perhaps as well impairs the quality of such farm products as
(C) perhaps also impairs the quality of such farm products like
(D) may also impair the quality of such farm products like
(E) may also impair the quality of such farm products as


We will proceed with the splits.
1. If we see the last word in the answer choice, they are like vs as.
By using this logic, we will have two answer choices left, B and E.

2. If we will look B and E, we will see the difference is between, impairs and impair. There seems S-V issue.
What is the subject?
Farm animals - (Plural )
By using this logic, we will be left with answer choice E.

Right answer is E.

1) The subject is not "farm animals" but "indoor air pollution"

2) The verb "impair" here drops the "s" because it is preceded by a modal verb, not because of S-V agreement.

Hope it helps

I'm not an expert but this is what i thought about B.

Indoor air pollution can threaten the health of closely confined farm animals and the workers who tend them and perhaps as well impairs the quality of such farm products like eggs, poultry, and pork.

(A) perhaps as well impairs the quality of such farm products like
(B) perhaps as well impairs the quality of such farm products as
(C) perhaps also impairs the quality of such farm products like
(D) may also impair the quality of such farm products like
(E) may also impair the quality of such farm products as

After identifying idiom 'such as' - used for presenting examples, the question is what is parallel to 'can threaten'. Only E has 'may impair' that makes sense.
In B, 'as well' after using 'and' ruins the meaning. Meaning-wise the two verbs - threaten and impair - are of equal importance.

HTH.
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Thank you very much, now I think I got it!

The word "perhaps" indicates that we aren't sure whether indoor air pollution impairs the quality. Consider the following examples:

• "Smoking may increase the risk of lung cancer." - The word "may" indicates that we aren't sure about the claim that smoking increases the risk of lung cancer.
• "Smoking increases the risk of lung cancer." - This is a factual statement: smoking DOES increase the risk of lung cancer.
• "Smoking perhaps increases the risk of lung cancer." - The tense of the verb "increases" suggests that we are stating a fact (as in the previous example). But the word "perhaps" indicates that we aren't sure. So there's a discrepancy here.

The first option is a clearer way to express the uncertainty of the claim. Choice (E) is more clear than choice (B) for the same reason.

For more on the verbs in choices (B) and (E), check out this post.
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Usually, too/as well is used at the end of the Sentence. also can be used as an adv in the middle.

Hi GMATNinja daagh

I am not clear of the distinction between your 1st and 3rd example. would really appreciate if you can elaborate more to eliminate btw B and E. May and perhaps to me appear to be doing the same purpose - bringing unsurity. but the official explanation states that B is wrong because of "as well". How is as well different from also?

I eliminated options A and B because of the redundancy “perhaps as well” and then from options C, D and E, I chose E because it had the correct idiomatic construction i.e: such as.

Please tell me if my approach is correct..

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