Hydrocarbons, with which fruit flies perfume themselves in species-specific blends, are known to be important in courtship, and apparently this assists flies that taste the hydrocarbons on prospective mates to distinguish their own species from that of others.
A. and apparently this assists flies that taste the hydrocarbons on prospective mates to distinguish their own species from that of
B. and apparently this assists flies when they taste the hydrocarbons on prospective mates in distinguishing their own species from those of
C. which apparently assists flies that tastes the hydrocarbons on prospective mates in being able to distinguish their own species from
D. apparently assisting flies to taste the hydrocarbons on prospective mates to distinguish their own species from those of
E. apparently assisting flies that taste the hydrocarbons on prospective mates in distinguishing their own species from

A is wrong because "this " is ambiguous and also "from that of "
B is wrong "when"
C being
betwen D and E why D is wrong because if we say "their own species from those of others" so those refers to species or technically to whole "their own species " or there are other errors in D.
Please explain
This is GMAT Prep Question

choice d: you're right that 'those of others' is problematic; it should just be 'others' (it's clear that the intention is to refer to other species, not to something of other species).

another huge problem with choice d is its total distortion of the sentence's original meaning.
- the original meaning is that hydrocarbons assist those flies that happen to taste them in species identification.
- choice d asserts that hydrocarbons somehow help flies to taste hydrocarbons (other ones?) with the intention** of species identification, which is a whole different ballgame.

**the infinitive can signal intention, or purpose, in this sort of context. for instance,
i ran over the glass in the road, flattening my tire --> the flattening of the tire was a result, but no information is given as to whether i intended it (i probably didn't)
i ran over the glass in the road to flatten my tire --> for some reason, i actually wanted to flatten the tire, so i chose this particular method of doing so.

Thanks for the nice explanation. Can you also please tell whether "assist in" is correct or "assist to" is the correct idiom - if at all there is a rule?

Thanks

good question.

from what i've seen, 'assist ... in' is the generally preferred form. i'm not so confident as to say that 'assist X to do y' is just plain wrong, but 'in' is preferred.

in any case, check out the official explanations (the ones appearing in the o.g.). if they tell you that 'assist ... to' is unidiomatic / awkward / whatever, then take that as gospel in the future.

D. apparently assisting flies to taste the hydrocarbons on prospective mates to distinguish their own species from those of
E. apparently assisting flies that taste the hydrocarbons on prospective mates in distinguishing their own species from

the modifier is placed so far away from the Subject ???

and of course... it is not modifying are know to be important ??


Ron Please help

Ron could you please also explain what others is referring to ??

OWN species or just species ??
own would act as a qualifier here..right ?

check out the parallelism:
...in distinguishing their own species from others

according to that parallel structure, "others" must refer to other species, since that's the only way in which logical parallelism can be achieved.

which modifier? you mean the "assisting ... in" modifier?
that's an adverbial modifier: "-ing" followed by a comma. it modifies the action or main verb of the most proximate clause: in this case, "are known to be important in courtship".

Hi Ron,

"Assist X in Y" should be preferred over "Assist X to do Y" - I understand this part. However, shouldnt the sentence use "distinguish between X and Y" rather than "distinguish X from Y"?

Thanks!

nah, both of those are correct.

pardon the lecture, but 2 bad habits have been exposed here; i'll address both.

bad habit 1)
DO NOT QUESTION THE ANSWERS TO OFFICIAL PROBLEMS.
it is a complete waste of your time to question such answers -- they are official, and so everything in them MUST be correct according to the exam writers.
occasionally the OG answer keys contain things that are weakly worded, hard to understand, rather meaningless, or (thankfully rarely) actually incorrect, but the actual problems don't contain such errors.
even in problems in which we instructors hold a firm conviction that the official answer is questionable/wrong, we must just bite our lips and treat that answer is correct. (see, for instance, #30 in the verbal supplement -- the question about thomas eakins, which uses an idiom "disturbing to his own time" that is wrong according to almost any other reasonable source.)

so, if you really don't like the answer to an official problem,
the WRONG questions to ask are
* "isn't that wrong?"
* "shouldn't that be ...?"
note that the answers to these questions are ALWAYS "no" and "no", since it's an official answer.

the RIGHT question to ask is
* "hmm, interesting, a structure with which i'm not familiar. what is this structure, when does it appear, and how is it used?"

bad habit 2)
IF ONE FORM OF A CONSTRUCTION IS CORRECT, DO NOT ASSUME THAT ALL OTHER FORMS OF THE CONSTRUCTION ARE INCORRECT.
this is going to get you in a lot of hot water, since there are plenty of constructions that are correct in multiple ways.
for instance, in this particular problem, note that both "distinguish between X and Y" and "distinguish X from Y" are legitimate idioms.

of course, this is going to make your studies more complicated, because you can no longer throw out all alternative versions upon learning some construction.

@ zarak_khan

by the way, i should probably mention that there was an incorrect idiom in your last post.
"prefer X over Y" is incorrect; it's considered redundant, because the word "prefer" already carries the meaning of "one thing over another".
the correct idiom is "prefer X to Y".

That really made me laugh...I sometimes feel sad for you guys in the frontline...

But I am sure atleast one of you should have some contact with the GMAC and can influence them in some say to correct a problem...if at all you find one...anyway this is out of scope...

So I wanted to know is the phrase "those of others" always incorrect?

no, as long as both "those" and "others" are actually parallel to something.

if your views are sufficiently different from those of others in the group, you may find discussion impossible.
--> "those" = "views"
--> "your" and "of others (in the group) are parallel

"in distinguishing their own species from those of others"

Can I say "others" is parallel with "their" and "those" is parallel with "Species"?

Hi xyin,

You are trying to match word for word and you should not do that with parallelism. It may work in some cases but try and make sure the elements are logically and structurally parallel.

Regards

Sunil