Scientists believe that unlike the males of most species

[vivekwrites]

Scientists believe that unlike the males of most species of moth, the male whistling moths of Numbing, Australia, call female moths to them by the use of acoustical signals, but not olfactory ones, and they attract their mates during the day, rather than at night.
a) by the use of acoustical signals, but not olfactory ones, and they attract
b) by the use of acoustical signals instead of using olfactory ones, and attracting
c) by using acoustical signals, not using olfactory ones, and by attracting
d) using acoustical signals, rather than olfactory ones, and attract
e) using acoustical signals, but not olfactory ones, and attracting

OA is D. Why is A wrong? I think D is incorrect. Simplified sentence is:
Male moths call female moths ,and attract ........ Why is there a comma before and. Since and is joining two verbs, there should not be a comma before. A comma will be there if and joins two clauses which is not the case here or and joins more than two objects.

[stock.mojo11]

Scientists believe that unlike the males of most species of moth, the male whistling moths of Numbing, Australia, call female moths to them by the use of acoustical signals, but not olfactory ones, and they attract their mates during the day, rather than at night.
a) by the use of acoustical signals, but not olfactory ones, and they attract
b) by the use of acoustical signals instead of using olfactory ones, and attracting
c) by using acoustical signals, not using olfactory ones, and by attracting
d) using acoustical signals, rather than olfactory ones, and attract
e) using acoustical signals, but not olfactory ones, and attracting

OA is D. Why is A wrong? I think D is incorrect. Simplified sentence is:
Male moths call female moths ,and attract ........ Why is there a comma before and. Since and is joining two verbs, there should not be a comma before. A comma will be there if and joins two clauses which is not the case here or and joins more than two objects.

They in A does not have a clear antecedent. they could refer to males of most species of moth or male whistling moths of Numbing, Australia

D is correct because call and attract are parallel.

Ask this Q, what do male whistling moths of Numbing, Australia?

Call ( how they call is not the parallelism issue here )

attract.

Hence D

[RonPurewal]

to the original poster:

i hear you on the comma.

however, here's the problem: that comma is not actually part of the "X and Y" construction.
instead, it's one of the two commas that box in the modifier "rather than olfactory ones". it's actually completely independent of the "X and Y" construction.

here's another example:

Two cities will host the fair: Duluth and Superior.
Two cities will host the fair: Duluth, which is in Minnesota, and Superior, which is in Wisconsin.

[wuziwu]

I have a problem in understanding why "They" in A does not have a clear antecedent. Since in A "and" separats two independent clauses. Should "they" in the second cluase refer to the subject of the first clause?(is it a rule for that?) Also, if the antecedent of "they" is unclear, why "them" & "their" in the unhighlighted part are OK? In my angle, they point at the same noun, another reason supporting that "they" has clear antecedent.

Please help

Scientists believe that unlike the males of most species of moth, the male whistling moths of Numbing, Australia, call female moths to them by the use of acoustical signals, but not olfactory ones, and they attract their mates during the day, rather than at night.
a) by the use of acoustical signals, but not olfactory ones, and they attract
b) by the use of acoustical signals instead of using olfactory ones, and attracting
c) by using acoustical signals, not using olfactory ones, and by attracting
d) using acoustical signals, rather than olfactory ones, and attract
e) using acoustical signals, but not olfactory ones, and attracting

OA is D. Why is A wrong? I think D is incorrect. Simplified sentence is:
Male moths call female moths ,and attract ........ Why is there a comma before and. Since and is joining two verbs, there should not be a comma before. A comma will be there if and joins two clauses which is not the case here or and joins more than two objects.

They in A does not have a clear antecedent. they could refer to males of most species of moth or male whistling moths of Numbing, Australia

D is correct because call and attract are parallel.

Ask this Q, what do male whistling moths of Numbing, Australia?

Call ( how they call is not the parallelism issue here )

attract.

Hence D

[deadpig1987hahaha]

what is the different between "rather than\instead of" and ",[but] not...,"?
OG10 says in A, the use of "but not" does not clearly convey that most other moths use olfactory signals"
and I cant understand this.
please explain!
thanks!

[chuckberry007]

Is d) parallel? d) using acoustical signals, rather than olfactory ones, and attract


Using A, rather than B, and attract.....why not attracting ??

Thanks.

[vijaya.ravinuthala]

"Rather than" is usually used for verbs and "Instead of" for nouns.
In option D "rather than olfactory ones" has noun. shouldn't the answer be E?

[RonPurewal]

@ original post

OA is D. Why is A wrong? I think D is incorrect.

stern lecture time:

DO NOT QUESTION OFFICIAL ANSWERS.
OFFICIAL ANSWERS ARE CORRECT.
you are completely wasting your time by questioning correct answers, since EVERYTHING in them is considered valid.

it's ok to ask why a correct answer is correct, but it's a waste of your time and resources to rail against an officially correct answer and claim that it's incorrect.

end stern lecture.
:)

for response to the original post, see my first post, above.

[RonPurewal]

Is d) parallel? d) using acoustical signals, rather than olfactory ones, and attract


Using A, rather than B, and attract.....why not attracting ??

Thanks.

hi -

you can't just make random words parallel. parallelism is restricted to words that actually represent PARALLEL CONCEPTS in the sentence.

the two MAIN VERBS in the sentence are "call" and "attract". THOSE two verbs should be parallel.
"using" is a MODIFIER that modifies the "call" clause. this is as it should be, since "using" is a subordinate idea (it just describes the way in which the calling is done - it's not another action parallel to the calling).

so "call" and "attract" SHOULD be parallel; these two verbs should NOT be parallel to "using".

[RonPurewal]

even i have same doubt as vijaya.

Rather than is usually used to show preference of verbs (or clauses) .but here it is used to show preference b/w 2 nouns. Is it correct usage?

"instead of" is generally restricted to nouns.

"rather than" can be used for essentially any part of speech at all.

they moved stiffly rather than gracefully (adverbs)
they moved to the left rather than to the right (prepositional phrases)
the car was red rather than blue (adjectives)
i bought a car rather than a truck (nouns) <–– this is the only sentence here that would work with 'instead of'
he chose to leave rather than continue arguing (infinitives)

...etc

there is also a difference in meaning, but that difference is much too slight to be relevant to this exam.

[ugenderr]

Ron,

I guess my concept is wrong here; can you please explain a bit more ..

I thought 'by the use of ..', an adverbial prep phrase in choices A, B, and C, modifies either the subject(the male whistling ..) or the verb (call), so just based on this concept, I eliminated D and E (and again participial phrase without comma modifies the preceding noun (here that noun is 'them')), making unwanted meaning?

I am not questioning official answer's validity, but I am trying to understand this concept a bit deeper.

so 'using acoustical signals' is modifying what? ( based on the official answer, it is probably modifying the verb call) ..

when/how you decide a participial phrase without comma modifies the verb? (or subject)? instead of preceding noun?

Thanks.

[RonPurewal]

Ron,

I guess my concept is wrong here; can you please explain a bit more ..

I thought 'by the use of ..', an adverbial prep phrase in choices A, B, and C, modifies either the subject(the male whistling ..) or the verb (call), so just based on this concept, I eliminated D and E (and again participial phrase without comma modifies the preceding noun (here that noun is 'them')), making unwanted meaning?

I am not questioning official answer's validity, but I am trying to understand this concept a bit deeper.

so 'using acoustical signals' is modifying what? ( based on the official answer, it is probably modifying the verb call) ..

when/how you decide a participial phrase without comma modifies the verb? (or subject)? instead of preceding noun?

Thanks.

this is a very good point -- this observation actually contradicts what we've seen so far from the gmat regarding the use of "no comma + -ing" modifiers.

we'll have to look for more examples; i certainly haven't seen any others that i remember.

[pradeepchandy]

please explain why option D preferred to option A?

The only reason I can see is D is more concise than A?


I rarely change option A when its clear and correct - Should I re-think my strategy based on this question , to account for "conciseness"

[RonPurewal]

please explain why option D preferred to option A?

The only reason I can see is D is more concise than A?


I rarely change option A when its clear and correct - Should I re-think my strategy based on this question , to account for "conciseness"

another reason why choice (a) is incorrect is its use of "by the use of..."

SUBJECT + ACTIVE VERB + BY + NOUN is generally incorrect.**
SUBJECT + ACTIVE VERB + BY + VERBing is generally correct, if "VERBing" is the method or process by which the ACTIVE VERB is carried out.
e.g.
i prepared for the test by studying flash cards --> CORRECT
i prepared for the test by the study of flash cards --> INCORRECT

on the other hand,
SUBJECT + PASSIVE VERB + BY + NOUN is an absolutely fundamental form, if the NOUN is the thing/person that did the action to the SUBJECT.
e.g.
james was seen by two witnesses. --> CORRECT

--

** the only exceptions to this occur in the case of special idiomatic expressions. for instance, "by candlelight" is a known idiomatic expression, so constructions such as "i studied by candlelight" are correct.

[supratim7]

Ron,

I guess my concept is wrong here; can you please explain a bit more ..

I thought 'by the use of ..', an adverbial prep phrase in choices A, B, and C, modifies either the subject(the male whistling ..) or the verb (call), so just based on this concept, I eliminated D and E (and again participial phrase without comma modifies the preceding noun (here that noun is 'them')), making unwanted meaning?

I am not questioning official answer's validity, but I am trying to understand this concept a bit deeper.

so 'using acoustical signals' is modifying what? ( based on the official answer, it is probably modifying the verb call) ..

when/how you decide a participial phrase without comma modifies the verb? (or subject)? instead of preceding noun?

Thanks.

this is a very good point -- this observation actually contradicts what we've seen so far from the gmat regarding the use of "no comma + -ing" modifiers.

we'll have to look for more examples; i certainly haven't seen any others that i remember.

Any final word on this? Can we say that "No comma + -ing modifier" can modify both the preceding action and the preceding noun/pronoun/noun phrase?

Many thanks | Supratim