certain breeds of dog are renowned for their sense

[ugenderr]

Source :gmatprep
Answer: C

Though certain breeds of dog are renowned for their sense of smell, there is often a greater difference in scenting ability between two members of a single breed as there is between members of different breeds.
 
(A) is often a greater difference in scenting ability between two members of a single breed as there is
(B) is often more difference in scenting ability between two members of a single breed as to find one
(C) is often a greater difference in scenting ability between two members of a single breed than
(D) are often greater differences in scenting ability between two members of a single breed as there are
(E) are often greater differences in scenting ability between two members of a single breed than there is

I can eliminate A, B and D based on the idiom ('more.... than', or 'greater... tha'n as opposed to 'greater ...as', or 'more ...as')

So now it is between C and E, and I chose E, which is wrong.

Can some one explain me these two choices? specifically, my question is why we dont need 'there is' at the end of option E?;having 'there is' makes more parallel right?

Thanks.

[shingchen]

I think choice (E) wrong because two verbs in this choice are not in the same quantity.

(E) there are often greater differences in scenting ability between two members of a single breed than there is

[RonPurewal]

I think choice (E) wrong because two verbs in this choice are not in the same quantity.

(E) there are often greater differences in scenting ability between two members of a single breed than there is

perfect.

[kvitkod]

Whether difference and differences are equal and we can use both options?

I think there is a subtle meaning difference, but I can't imagine that the GMAT would try to use this as the distinction between a correct and a wrong answer. They are quite close is meaning, although I think "difference" is slightly superior, since "difference" refers to a singular difference and "differences" refers to multiple differences. In this sentence only one category of difference is mentioned.

[jnelson0612]

Whether difference and differences are equal and we can use both options?

I think there is a subtle meaning difference, but I can't imagine that the GMAT would try to use this as the distinction between a correct and a wrong answer. They are quite close is meaning, although I think "difference" is slightly superior, since "difference" refers to a singular difference and "differences" refers to multiple differences. In this sentence only one category of difference is mentioned.

I agree with your analysis. Because there is only one category mentioned (sense of smell) I think the word "difference" is appropriate. However, notice that if you just use the basic grammar rules you don't even have to worry about this, and I highly doubt that the GMAT would use something like this as the difference between a right and wrong answer.

[gmatkiller_24]

HI, Ron. I got some thoughts here about the split between more and greater, and also between difference and differences

as to the first one,

more can be easily out because of ambiguity: either refers to "number of differences" or to "degree of differences"

greater is better

as to the second one,

since we are talking about the degree of difference between two groups, we don't need the plural one " differences" (it just don't make sense)

Please correct me if I am wrong . Thank you very much

[RonPurewal]

more can be easily out because of ambiguity: either refers to "number of differences" or to "degree of differences"

greater is better

you will not be responsible for this sort of thing-- it's too subtle/idiomatic to be necessary.

in choice B -- the only choice with "more" -- there is an absolutely atrocious lack of parallelism (there is definitely nothing that corresponds to "to find one").
so that choice is gone, and "more"/"greater" is a non-issue.

if you see small/subtle/idiomatic differences, especially in word choice, they are almost certainly included to distract you from MUCH bigger/more fundamental problems (such as the lack of parallelism in choice B).

[RonPurewal]

since we are talking about the degree of difference between two groups, we don't need the plural one " differences" (it just don't make sense)

Please correct me if I am wrong . Thank you very much

this is the right idea-- we're talking about only one KIND of difference (namely, the difference in smelling ability).

the plural "differences" would be correct only if we were actually discussing two or more distinct KINDS of "differences".