A peculiar feature of the embryonic mammalian circulatory system is that in the area of the heart the cells adhere to one another, beating in unison and adopting specialized orientations exclusive of one another.
(A) beating in unison and adopting
(B) they beat in unison while adopting
(C) beat in unison, and adopt
(D) beating in unison yet adopting
(E) even though they beat in unison and adopt

thanks
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Just to add to ^^
We can separate out A and D as we need -ing word after the comma (To show extended meaning of the clause before)

A peculiar feature of ......
hints for contradictory

I just joined this community and by far the best resource I've ever seen for gmat.

So....
Here's what's confusing about this question:

A peculiar feature of the embryonic mammalian circulatory system is that in the area of the heart the cells adhere to one another, beating in unison and adopting specialized orientations exclusive of one another.

Here, the underlined portion seems to act as an adjective clause modifying "the area of the heart." [read it as one clause before the comma and you'll see.] Without a comma between "heart" and "cells," the sentence lacks a clear subject after "another,"..So, my answer was B since it was the only one with a clear subject even though "they" is not referenced the best way, but it's better than the other choices.

The answer D makes sense to me if the question was:
A peculiar feature of the embryonic mammalian circulatory system is that in the area of the heart, the cells adhere to one another, beating in unison and adopting specialized orientations exclusive of one another.

Now there is a clear subject and D makes the most sense.

I hope I didn't add to the confusion here.

Here's my take on this question w/out repeating too much of what other people's said.

Since the last part of the sentence said, "beating in unison and adopting specialized orientations exclusive of one another.", we should see a contrasting triggering word to differentiate between "unison" and "exclusive of one another". Answer choices A, C, and E all used "and", for which it doesn't trigger the contrasting effect. Only B and D uses the right words - while (B) and yet (D).

Looking into B and D, B creates a common splice. In (B), "they beat in unison..." creates a complete sentence with a subject and a verb. In conjunction with the non-underlined sentence, the comma in between the two creates the grammatical error; therefore, (B) is incorrect. (D) fixes all the problems of this sentence.

In response to MrEasy's question with the comma after the word 'heart', I don't believe the comma is necessary since the material after the word 'heart' is a necessary clause, which requires no comma in between the two clauses. I hope I didn't confuse anyone with what I said. Also, just to go aside from that, people get bogged down by parts that are not underlined way too much; everyone should take what's given to them (the non-underlined portion) knowing that it's correct and don't question the non-underlined portion. I just wanted to point that side point out, though I'm pretty sure most people on this forum already knew that.
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Hey All,

Everybody seems to have the right answer, but just to make it clear, adding a comma would NOT improve this sentence. Answer choice C is hoping to get you with a kind of shallow parallelism. We want to differentiate between the main verb "adhere", and the two subordinate verbs. To make this all one list changes the meaning for the worse.

Hope that helps!

-t
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opton D , becoz it clearly follow parallelism and show contrast.

IMO D . Beating in Unison yet adopting
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Hi all,
i have understood the statement as :-

A peculiar featureof the embryonic mammalian circulatory system is that in the area of the heart the cells adhere to one another ...

The peculiar feature is that the cells adhere to each other.

If viewed from this angle, wouldn't option E make some sense?
Since it does introduce the contradiction with "Even though" and also maintains the parallelism with "adhere" by using "beat" and "adopt".


please provide your views on this.
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