Sentence Correction

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.

(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

Kindly explain the reasoning against each option!

thephoenix wrote: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.

(A) tell individual genes both when to become active and when to remain - Correct
(B) tell individual genes both at which time they should become active or should remain - Awkward
(C) tells individual genes both when to become active or remain - Eliminated
(D) tells individual genes both when to become active or when to remain - Eliminated
(E) will tell an individual gene both about when it should become active and remain - Wrong tense

"one of the substances" will take the plural verb TELL. Hence (C) n (D) Eliminated

(A) is correct

komal wrote:

thephoenix wrote: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.

(A) tell individual genes both when to become active and when to remain - Correct
(B) tell individual genes both at which time they should become active or should remain - Awkward
(C) tells individual genes both when to become active or remain - Eliminated
(D) tells individual genes both when to become active or when to remain - Eliminated
(E) will tell an individual gene both about when it should become active and remain - Wrong tense

"one of the substances" will take the plural verb TELL. Hence (C) n (D) Eliminated

(A) is correct

Adding on to that, usage of Idiom" both X and Y" is properly used in A

I am not very sure of "one of the substances" is singular or plural....but this idiom makes me choose A

Komal is right on that part "one of the subtances that...".

I've come across Ron's post in this forum explaning this in detail. Here is a summary of that info.

1) ONE OF THE X'S THAT/WHO <PLURAL> --> This category applies to this sentence
2) ONE OF THE X'S <SINGULAR>
3) ONLY ONE OF THE X'S <SINGULAR>
4) ONLY ONE OF THE X'S THAT/WHO <PLURAL>
5) THE ONLY ONE OF THE X'S <SINGULAR>

Hey papgust, thanks for your summary. Could you also provide the link to Ron's post which you have mentioned?