In a cardboard representation of nucleotide subunits, Watson and Crick

warrior1991 - you are correct that
• Option E is wrong

-- elaborated acts as a verb, not a participle
-- (E) sticks incorrectly sticks two verb phrases together with a comma but no conjunction
-- so the comma after elaborated . . .entirety is fatal.
-- The comma after Watson and Crick is also fatal.

The word AND without a comma should follow elaborated...entirety (see below)

Let's look at (E) as it stands:

In a cardboard representation of nucleotide subunits, Watson and Crick, elaborated on other scientists’ theories which had failed to explain the nucleotide structures and pairings in their entirety, accurately modeled the double-helix DNA.

Ignore the introductory prepositional phrase.
Watson and Crick , elaborated on other ABCs' work which had failed to explain XYZs in their entirety, accurately modeled the 123.

Wrong: Subject + elaborated on + COMMA + modeled

Here is a shorter example with identical structure.
Wrong: Karen, elaborated on her theory, modeled the atom correctly.

Corrected: Subject + elaborated on + AND + modeled (NO comma)
Correct: Karen elaborated on her theory and modeled the atom correctly.

Compare the two short example sentences.
It should be easier to see that (E)'s construction is wrong.

If option (E) is supposed to be a compound predicate (two verb phrases, i.e., two things that Watson and Crick did),
then it needs a comma + and after the "elaborated" phrase.

In that case, the comma after Watson and Crick is not justified.

The structure of (E) should be:

In a cardboard representation of nucleotide subunits, Watson and Crick elaborated on other scientists’ theories which had failed to explain the nucleotide structures and pairings in their entirety and accurately modeled the double-helix DNA.

• Option A is correct.

As far as meaning, logic, and sentence structure, (A) makes a lot more sense.
"elaborating" describes Watson and Crick in a way that elaborated cannot.

Jargon: the whole __ING phrase is called a reduced relative clause.
We could write
. . . Watson and Crick, who were elaborating on other scientists' theories that had failed to explain...

That construction makes sense.
It contains a relative clause. Who is the relative pronoun. Were is the verb in the relative clause, which describes Watson and Crick. In English, some clauses can be shortened, as is the case here.

We can "reduce" the relative clause who were elaborating on...
We just remove the who and the were.
Result: elaborating on other scientists'...

-- in the same way as the UNreduced relative clause does, the reduced clause still describes / modifies the nouns -- in this case, Watson and Crick

Option A, as it stands:
In a cardboard representation of nucleotide subunits, Watson and Crick, elaborating on other scientists’ theories which had failed to explain the nucleotide structures and pairings in their entirety,accurately modeled the double-helix DNA.

This structure in (A) is clear in meaning and logic.
It is also grammatically correct.

We can also check by shortening the sentence, this way:

Watson and Crick, elaborating on ABCs' incomplete theories, accurately modeled the XYZ.
Correct: Subject + comma + modifier + verb.

This OA [of (E)] is wrong.
I will change it to option (A).

I hope that analysis helps.

*we could NOT reduce what would be a relative clause containing elaborated, which could be written who had elaborated. We cannot reduce that relative clause in order to make elaborated a direct modifier of the two scientists because ... The past participle and the past tense verb are identical. elaborated is not acting as a modifying participle in this case.

Hi Mudit27021988 , this question's original OE was confusing.

Regarding the highlighted part, you should always reject an answer that is a comma splice.
A comma splice is wrong 100% of the time. No exceptions.

medus18 , yes.

On the GMAT, which begins a non-essential modifier and should be set off by a comma or by commas.

Occasionally you will see "of which" without commas, but that construct is different.

This source has a habit of using the British English approach, but that approach is not
the way that GMAT tests the issue.

British English: which and that are interchangeable
U.S. English: a debate, although most dictionaries note that formal U.S. writing experts require that for essential modifiers
On the GMAT and in many conventional grammarians' minds: that and which are not interchangeable.
that is for essential modifiers
which is for non-essential modifiers

All of the options in this question contain the same error,
so we can say that (A) is the best of the lot.

If the GMAT authors suddenly decide that which can take the place of that,
the authors almost certainly will not give you a choice.

They, too, will put which in all the answer choices.
I do not believe that such a change is coming anytime soon.

Hope that helps.

Hi generis

Got it finally! thanks a ton

Hi warrior1991,

generis is right: there are plenty of decision points around elaborated.
1. If elaborated is a modifier, the meaning is wrong.
2. If elaborated is a verb, there should be an and before accurately modeled and there should be no comma after Crick.
3. If elaborated is a verb, the meaning is not very clear. Did they do two separate things (elaborated and modeled)?

However, we are not looking at a run-on (a run-on involves at least two clauses). Also, have you been told that "-ed modifiers" can modify only nouns? If yes, that is not correct.

I am still confused why ing modifier will not be accepted here...Can someone please clarify..
Thanks

AjiteshArun Yes, I knew that '-ed' modifiers only modify the noun. But thanks for bringing this to light.

generis As usual, thank you for a fast and comprehensive response.

Debashis Roy - on the first page of the thread, other people
incorrectly rejected the ING modifier because
1) the OA was incorrectly listed as (E) rather than (A);

2) posters were trying to justify the [then incorrect] official answer; and

3) in their attempts to justify (E), posters used a very common misconception to justify (E).

People have been taught incorrectly that

comma + present participle phrase
can modify only a previous clause, not a noun.

They also incorrectly believe that only
comma + verbED
can modify a noun.

Those beliefs reflect at least one major prep company's approach, and apparently, Princeton's too.

The posters on the first page of the thread were repeating
inaccurate information in part because they had an inaccurate OA.

For their sake, I noted in this post above, that

comma + verbING can modify the immediately preceding noun.
It makes sense to you. It did not make sense to them when the OA was incorrectly listed as (E).

I hope that the earlier debate is now clear.

generis
Thanks I got it...I also selected A as the correct choice since E doesnt make sense in its structure

Debashis Roy , I know that you understand which answer is correct.

Perhaps I am mistaken, but you seemed to be wondering
why many others were not choosing as you did and
what all the hullabaloo was about.

I thought when you wrote, "Please clarify,"
you were asking for an explanation of much debate surrounding
what seemed to you to be a straightforward issue.

So I gave you the explanation that I thought you asked for.

If I misunderstood your question, please rephrase it.
I'll amend my answer above to make sure that it looks as if I am speaking of others. Regards.

generis

You got me perfectly! I was indeed confused seeing so many responses in favour of E...and you have clarified the matter regarding the wrongly listed correct answer...I appreciate your help..
Thanks again and cheers!

The correct answer is A, not E. Is it possible that they changed the key? Anyway, E doesn't make sense. If E were to be right answer, it would need a conjunction to put elaborately and accurately modelled in parallel. Because it is not, the answer is A - the modifier provides extra information - what they did en route to modelling the DNA.

I have a question regarding the absence of 'comma' before 'which'?.

Some people feel comfortable using a which the way they would use a that (without a comma). On the other hand, this is not an official question, so if you wanted to ask whether this usage is correct, the answer is that we can't be sure that it is correct.

For what it's worth, I'd look at something like this as a warning sign, not an "absolute".

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