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Source: Official Guide for the GMAT 13th Ed. Sentence Correction; #114 Official Guide for the GMAT 2015 14th Ed. Sentence Correction; #114


Starfish, with anywhere from five to eight

Starfish, with anywhere from five to eight arms, have a strong regenerative ability, and if one arm is lost it quickly replaces it, sometimes by the animal overcompensating and growing an extra one or two.

2 Explanations


Kunal Sachdeva

I have a Question on B, " And" at the end of the underlined part suggests, they are overcompensating and Growing.

However the meaning should be Overcompensating
!!How are they Overcompensating ,

Modifier Growing extra arm
, Yes I know I am wrong somewhere because official answers are always right. but i want to know whats the mistake i have done

Apr 28, 2017 • Comment


Hi Kunal,

Are you asking why the sentence says that the starfish overcompensating?

If the starfish loses 1 arm, but replaces it by growing 2-3 arms (an "extra" 1 or 2), then they have overcompensated for the loss of the one arm.

Does that answer your question?

Apr 28, 2017 • Reply

Pulkit Aggarwal

Hi Adam,

I have a similar question, as Kunal has. In C, the ".......Overcompensating, Growing 1 and 2 extra arm..." is better because growing is adverbial modifier- modifying the complete phrase before the comma.

While in option B it seems that if the starfish losses 1 arm it replaces it quickly, with the animal overcompensating and with the animal growing extra hand. ( IMO overcompensating and growing 1/2 arm is a redundant sentences , trying to convey same meaning twice)

But since the option C is wrong. I will try to answer this- Can it be because in option B the modifier " growing...." Does not have a complete subject+verb pair in previous prepositional phrase (Sometimes by the animal overcompensating), also Verb+ing modifier should have a clear subject , and if I try to complete the previous prepositional phrase - The arm is replaces by the animal. The arm becomes the illogical subject.

Aug 4, 2017 • Reply


Hi Pulkit,

Mike has discussed this question extensively over at GMAT Club:

I'm going to paste some of what I think is most relevant, and note that Mike doesn't think this is a good GMAT question:

I realize this is an official question, but I would call this problem one of GMAC's clunkers. It has a clear answer, but it falls short of the standards that the GMAT normally has on SC. In particular, the "with" + [noun] + [participial phrase] structure, as a substitute for a clause, is often something GMAC has considered wrong in other, better written questions, but here it is simply unavoidable. To umeshpatil, I would say: in the active voice, neither "with" nor "by" is ideal; for a new action, ideally we should have a whole new clause.

Finally, for the split at the end: this is one respect in which (B) is not ideal. I think it is awkward to put those two participles in parallel, "overcompensating and growing ..." Really, those are not two separate actions. Instead, the latter is an explanation of the former: what do we mean that starfish "overcompensates"? We mean that the starfish sometimes grows extra arms. It is an explanation of the same action, not a new action. Therefore, I think putting the two participles in parallel is less than ideal. It would be much better to give them the relationship that (E) has: "overcompensating, [that is to say] growing ..."

So, (B) has nothing that is clearly, unambiguously wrong, but it has some "shades of gray" problems. What makes it the right answer is that each other answer has something definitively wrong about it. Choices (A) & (C) & (D) all make trainwreck pronoun errors, so they are not even possibly correct.

Aug 21, 2017 • Reply


Gravatar Mike McGarry, Magoosh Tutor

May 25, 2013 • Comment

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