The human growth hormone, made by the pituitary gland, is secreted dur

'D' is the best.

(A) during sleep in higher concentrations than when awake **incorrect usage of when. Harmones does not awake****
(B) when sleeping in higher concentrations than waking hours **same as in A***
(C) in higher concentrations during sleeping than waking ***'during sleeping is compared to 'waking'*****
(D) in higher concentrations during sleep than during waking hours ****CORRECT***
(E) in higher concentrations when asleep than when awake ****Same as in 'A'***

D is correct.

E may imply that the hormone itself is asleep or awake.

but why cannot D mean that it is secreted during the hormone's sleep rather than its waking hours? I mean, is there rule that explain the difference between using D and E?

Hi gmatninja,

One small query wrt Choice E: Is the Comparison right in terms of singular/plural, as SLEEP looks to be singular and WAKING HOURS is plural.

Please CLARIFY,

Regards.

Posted from my mobile device

Here's the official explanation provided by the GMAC for this question:

The sentence describes a difference between being asleep and being awake with respect to secretion of the human growth hormone which is secreted in higher concentrations during sleep. The word than is correctly used to make the comparison, except that the phrases during sleep and when awake are not parallel as required. The phrase during sleep is an adverbial modifier of the verb is secreted, but the phrase when awake is an elliptical clause; when [“person X” is] awake, where “person X” should refer to something that could be awake (we know something refers to a person because the sentence is about the human growth hormone). Therefore, the lack of reference to a person indicates that when awake is incorrect in this context.

Option A: This is incorrect for the reasons given above.

Option B: The sentence contains no reference to a person to whom the verbal adjective sleeping can appropriately apply. The adverbial phrase in higher concentrations should precede sleeping to avoid a reading that seems odd, given that sleeping does not come in varying concentrations. Also, the placement of the phrase immediately before than seems to absurdly compare concentrations with waking hours. Alternatively, but equally absurd, the sentence could be read as comparing the human growth hormone with waking hours.

Option C: There is a failure of parallelism in that during is needed in the second part of the comparison as well as in the first. Also, the noun sleep would be preferable to the verb-derived noun form sleeping following during (this consideration also makes waking, the form parallel to sleeping, less suitable).

Option D: Correct. The phrases during sleep and during waking hours are parallel as required for comparisons that use than.

Option E: Although when asleep is parallel with when awake, there is no reference to a person to whom the adjectives asleep and awake can apply. This wording absurdly seems to attribute these adjectives to the human growth hormone itself.

The correct answer is D.

Please note that I'm not the author of this explanation. I'm just posting it here since I believe it can help the community.

Hi Experts,

I was able to eliminate the two options A,B. But I got confused with the parallelism part.
Option C, looks like there is comparison is between the gerunds.
However Option E, looks like the comparison is between nouns.

How parallelism worked in Option D? please explain.

Thanks in Advance.

Keshav1404

We don't need the same word forms after "during" as long as we have phrases that can be parallel. "During sleep" and "during waking hours" are both adverbial modifiers that describe when something happens, so they are parallel.

C is comparing "during sleeping" with just "waking." Those aren't parallel. We need the second "during" to show that we are comparing when something happens, not the states themselves. (In other words, we don't want to compare nouns, and that's what gerunds are.)

E isn't comparing nouns; it's comparing adverbial modifiers: "when asleep" and "when awake." It's fine to make these parallel; however, they don't make sense in the sentence. No person/animal is mentioned, so there's no one for "when asleep" to describe.

DmitryFarber
But in option C, Why 'During' cannot be applied to both Sleeping and Waking?

Because we're in the middle of a comparison: HIGHER (during sleeping) THAN . . . . We need "during waking" for this to work. HIGHER/THAN creates a pair of closed parallel markers. These typically require us to be very strict with parallelism to make the structure make sense. For instance, I can't say "I'm more creative at home than school."