Biologists believe that they have found one of the substances that tel

HI GMATNinja , generis , AndrewN , GMATCoachBen GMATGuruNY

Can you please help me with this problem.

How would that refers to substances ? one of the substances tells individual genes right but not all the substances.

Can you correct me ?

Hi,

If you scroll one post above you will find my post that details the sentence structure of this SC questions.

If you focus on the sentence structure and especially the meaning analysis you will see that the "Biologists" found one of the substances What kind of substances? "The ones that tell individual genes..."

The relative pronoun modifier beginning with "that" is simply modifying the noun "substances" and that is correct! We are essentially saying that
(1) the Biologists found one of the many substances.
(2) These substances are those that tell genes when to become active and when to remain quiescent

Hi hope this helps

John is THE ONLY ONE of the members WHO IS PLANNING TO ATTEND.

Here, John is THE ONLY ONE planning to attend.
No other members are planning to attend.
In other words:
Of the members, John is THE ONLY ONE WHO IS PLANNING TO ATTEND.
Since John is THE ONLY ONE, IS PLANNING is correct.

John is only one of THE MEMBERS WHO ARE PLANNING TO ATTEND.

Here, many members ARE PLANNING to attend.
John is ONLY ONE of these members.
In other words:
Of the MEMBERS WHO ARE PLANNING TO ATTEND, John is only one.
Since John is not THE only one -- other members ARE PLANNING to attend -- a plural verb is needed here.



Biologists...have found one of the substances that tell individual genes...when to become active.
Here, many substances TELL genes when to become active.
Scientist have found ONE of these substances.
In other words:
Of all the SUBSTANCES THAT TELL GENES WHEN TO BECOME ACTIVE, one has been found by biologists.
Since many substances TELL genes when to become active, a plural verb -- tell -- is required.

Hello, NandishSS. I agree with what has been written already in response to your query. In fact, reading over the reply by GMATGuruNY reminded me of a similar dialogue that you and I had engaged in on a different question. Rather than piggyback off of an already fine and detailed analysis to this that question, I would urge you to revisit that other dialogue, here.

Happy reading, and thank you for thinking to ask me about this one.

- Andrew

NandishSS, This is a common source of confusion, thanks for asking me. I see that there are already excellent explanations to your question by other experts above. I will only add:

The singular "tells" is a tempting trap, because we are often crossing off the "of X" modifier to find the subject. The difference here is the word "that", which modifies "substances" to create the intended meaning -- "found one of (multiple) SUBSTANCES that TELL"

For example:

ONE of the dogs IS gold.

ONE of the DOGS that LIVE here IS gold.

Here is another similar question for you to try: https://gmatclub.com/forum/with-a-new-p ... 89983.html

There are also more details and examples from Ron Purewal's notes here: https://gmatclub.com/forum/subject-verb ... l#p1129636

HI AndrewN , GMATCoachBen , GMATGuruNY

Thank you. I got it now.

Biologists believe that they have found one of the substances that tell individual genes both when to become active and when to remain quiescent in the earliest phases of an embryo’s development.

'substances' is plural; we need plural 'tell'. Eliminate C and D.

The use of 'about' in E is incorrect.

In Choice B the use of 'or' is incorrect. Since we have 'both' earlier in the sentence, 'and' is required.

Answer is A.

(A) tell individual genes both when to become active and when to remain

(B) tell individual genes both at which time they should become active or should remain

(C) tells individual genes both when to become active or remain

(D) tells individual genes both when to become active or when to remain

(E) will tell an individual gene both about when it should become active and remain

Biologists believe that they have found one of the substances

Shouldn't presence of "one" in the sentence require "singular" verb tell?

Dear Friends,

Here is a detailed explanation to this question-

Meaning is crucial to solving this problem:
Understanding the intended meaning is key to solving this question; the intended meaning of the crucial part of this sentence is that the substances tell individual genes when to become active and when to remain quiescent.

Concepts tested here: Subject-Verb Agreement + Meaning + Tenses + Idioms

• “both A and B" or "A as well as B" are the correct usages; A and B must be parallel and comparable.
• Statements of universal fact are best conveyed through the simple present tense.
• The simple future tense is used to refer to actions that will take place in the future.

A: Correct.
1/ This answer choice correctly refers to the plural noun "substances" with the plural verb "tell".
2/ Option A correctly uses the idiomatic construction "both A ("when to become active") and B ("when to remain...development")", maintaining parallelism between A and B and thus conveying the intended meaning - that the substances tell individual genes when to become active and when to remain quiescent.
3/ Option A correctly uses the simple present tense verb "tell" to refer to a statement of universal fact.
4/ Option A is free of any awkwardness or redundancy.

B:
1/ This answer choice incorrectly uses the unidiomatic construction "both A ("at which time they should become active") or B ("should remain quiescent...development")", leading to an incoherent meaning; the intended meaning is that the substances tell individual genes when to become active and when to remain quiescent; remember, “both A and B" or "A as well as B" are the correct usages; A and B must be parallel and comparable.
2/ Option B uses the needlessly wordy phrase "at which time they should become active", leading to awkwardness and redundancy.

C:
1/ This answer choice incorrectly refers to the plural noun "substances" with the singular verb "tells".
2/ Option C incorrectly uses the unidiomatic construction "both A ("when to become active) or B ("remain quiescent...development")", leading to an incoherent meaning; the intended meaning is that the substances tell individual genes when to become active and when to remain quiescent; remember, “both A and B" or "A as well as B" are the correct usages; A and B must be parallel and comparable.

D:
1/ This answer choice incorrectly refers to the plural noun "substances" with the singular verb "tells".
2/ Option D incorrectly uses the unidiomatic construction "both A ("when to become active") or B ("when to remain quiescent...development")", leading to an incoherent meaning; the intended meaning is that the substances tell the individual genes when to become active and when to remain quiescent; remember, “both A and B" or "A as well as B" are the correct usages; A and B must be parallel and comparable.

E:
1/ This answer choice incorrectly uses the simple future tense verb "will tell" to refer to a statement of universal fact; remember, statements of universal fact are best conveyed through the simple present tense, and the simple future tense is used to refer to actions that will take place in the future.
2/ Option E fails to maintain parallelism between A ("about when it should become active") and B ("remain quiescent...development") in the idiomatic construction "both A and B"; remember, “both A and B" or "A as well as B" are the correct usages; A and B must be parallel and comparable.
3/ Option E uses the needlessly wordy phrase "about when it should become active", leading to awkwardness and redundancy.

Hence, A is the best answer choice.

To understand the concept of "Simple Tenses" on GMAT, you may want to watch the following video (~2 minutes):



All the best!
Experts' Global Team

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