Although all dogs are descended from the wolf and the jackal, the vari

Although all dogs are descended from the wolf and the jackal, the various breeds of dog are so different from one another that it hardly seems possible that they had a common ancestry.

We can easily eliminate C, D and E

Now between A and B

First:

From one another - Used when there are more than one entities for comparison

From each other - Used when there are two entities for comparison

(Though normally many experts believe that both can be used interchangeably)

Second:

They had - This is correct here as the event is in the past and the ancestors are not alive at this point in time

They have - Implies that the ancestors are still alive, which is incorrect

Though this question is debatable. Hence, Its A

I'll weigh in, but perhaps no one will be satisfied, as there is no definitive way to choose between A and B. Given a choice between "each other" and "one another," I'd probably go with "one another," since some people find this better for referring to relationships among multiple things (not just two). However, I have no indication that the GMAT relies on this as a rule. On the contrary, it's common to see SC questions that split between two interchangeable terms as a "fake-out" split, when something else is really at issue.

As for "have" vs. "had," I would personally prefer "have." I would use "had" only if we were describing someone's belief from the past (e.g. "Darwin realized that humans and apes had a common ancestry"). Since there's no need to clarify the order of things here, past perfect doesn't accomplish anything. Does that make "had" definitively wrong? Not really. It partly comes down to the ambiguous meaning of the word "ancestry." If it's meant to refer to your line of descent, as in a family tree, it makes sense to think of that as present. If it's meant to refer to the process by which you came about, then that's more clearly situated in the past only, and so one could argue that "have" doesn't make sense.

So what would happen if we clarified by replacing "ancestry" with "ancestor"? Even then, either "had" or "have" could be appropriate. With "had," we'd be emphasizing that at one time, this ancestor existed. With "have," we'd be emphasizing that each breed can still trace back to this common ancestor. This flexibility is common with perfect tenses. Their point is to allow for emphasis and clarity. In this case, the sequence of events doesn't need clarifying (we know that the ancestor existed before modern dogs), so there's no way to say that one version must be used.
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The answer is A as follows.

2 concepts are tested here.
1. Subject verb agreement - breeds will take plural verb
2. Use of "one another" when more than 2 items are compared.


(A) are so different from one another that it hardly seems possible that they had a common ancestry. - [Correct] Use of "are" is consistent with breeds. "one another" is correctly used to compare more than 2 breeds
(B) are so different from each other that it hardly seems possible that they have a common ancestry. - "each other" is wrongly used
(C) are so different, one from another, that their having a common ancestor hardly seems possible. - "one from another" is the main problem here. However there are many more issues with this sentence.
(D) being so different from one another makes it hard to believe that they had a common ancestry. - Use of "being" is usually wrong in GMAT
(E) that having a common ancestry hardly seem possible in that they are so different from one another - Whole construction seems awkward. No reason to choose this when clear and simple choice A is avaialbe

ydmuley they had implies,, the common ancestry is no more existing.... actually the ancestry is still existing,,,
the question looks debatable on meaning issue,,,

can any experts pitch in please....

can anyone explain what "it" refers to in the option A??

"It" refers to "author's thought" that various breeds of dog are from common descendants i.e. wolf and the jackal.

Sent from my SM-J700F using GMAT Club Forum mobile app

ohk.........but is it not necessary that it should be somewhere written in the sentence or we can hypothetically think that.

Please refer this link https://gmatclub.com/forum/placeholder-it-111879.html

Sent from my SM-J700F using GMAT Club Forum mobile app

Hi,

The use of past perfect tense in the OA seems incorrect.

HI TheGMATcracker,, use of "had + past tense" is called past perfect..

In option A,, usage of they had implies simple past...

hope tat helps

can we have an expert explanation please?

Thank you for your explanation. I have locked this topic because of poor quality


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