why d is wrong,

[thanghnvn]

Reptiles, by drawing their body heat directly from the Sun rather than burning calories to generate it, can survive on ten percent of the nourishment that a mammal of similar size would normally require

A: rather than burning calories to generate it
B: rather than the generation of body heat by burning calories
C: and not from generating it by burning calories
D: instead of by burning calories for generating it
E: instead of body heat generated by burning calories

this is certainly from gmatprep, pack 1 software. oa is a

why D is wrong?
we should used "to do" not "for doing". is that the reason D is wrong?

[RonPurewal]

that idiom is wrong there, yes.

there's also the issue of "instead of...", which should be followed by a noun.
(this is not a special construction; it's the same thing you need behind "of" in general.)

[kenchung31]

Hi Ron,

Sorry I have a question that doesn't the pronoun of "it" in choice A create an ambiguous situation and how I should refer "it" to the "body heat" or "the sun" (both are expressed in singular)??

Thanks for your help!!

[RonPurewal]

Hi Ron,

Sorry I have a question that doesn't the pronoun of "it" in choice A create an ambiguous situation

officially correct answers are not wrong!
do not question them!
far too many students on this forum make the mistake of questioning the correct answers; please note that doing so is a complete waste of your time and effort. i.e., exactly 0% of the time that you spend posting "isn't this official answer wrong?" is productive, and exactly 100% of that time is wasted.

"is this correct?" is NEVER a productive question to ask about one of GMAC's correct answers -- the answer is always yes.
"is this wrong?" / "is this X type of error?" is NEVER a productive question to ask about one of GMAC's correct answers -- the answer is always no.

instead, the questions you should be asking about correct official answers, if you don't understand them, are:
"why is this correct?"
"how does this work?"
"what understanding am i lacking that i need to understand this choice?"

this is a small, but hugely significant, change to your way of thinking -- you will suddenly find it much easier to understand the format, style, and conventions of the official problems if you dispose of the idea that they might be wrong.

and how I should refer "it" to the "body heat" or "the sun" (both are expressed in singular)??

In context, it's obvious that "it" is body heat, and not the sun. Reptiles don't generate the sun by burning calories.

If the noun can be discerned by pure common sense, then it's not "ambiguous".

[RonPurewal]

More importantly (and more generally):

* The GMAT does not test "ambiguous pronouns".
Don't worry about them.
There's no upside -- and, as you see here, worrying about them can actually cause you to arrive at incorrect conclusions about things that are tested.

[lindaliu9273]

Hi Ron,

Can you explain further about the principle of "rather than"?(something like "instead of" can only be followed by noun)

Can it compare noun, verb or clause?

Thank you so much!

[RonPurewal]

Hi Ron,

Can you explain further about the principle of "rather than"?(something like "instead of" can only be followed by noun)

Can it compare noun, verb or clause?

Thank you so much!

This is addressed here (and in the following post):
post88284.html#p88284

[lindaliu9273]

Thanks a lot

[RonPurewal]

Thanks a lot

Sure.

[Shelley]

that idiom is wrong there, yes.

there's also the issue of "instead of...", which should be followed by a noun.
(this is not a special construction; it's the same thing you need behind "of" in general.)

hi Ron,
Would u mind explain why E is wrong?
Thank u very much~~~~~~~~

[RonPurewal]

that idiom is wrong there, yes.

there's also the issue of "instead of...", which should be followed by a noun.
(this is not a special construction; it's the same thing you need behind "of" in general.)

hi Ron,
Would u mind explain why E is wrong?
Thank u very much~~~~~~~~

The two methods of getting heat are...
• drawing body heat from the sun
• burning calories to generate it

E is non-parallel.

[Chi HoC263]

Hi Ron,

In correct Ans (A), I am trying to understand why there is no "by" in front of burning calories? is this ellipsis understood? I almost chose Ans (D) because of that.

Ans (A):
"rather than (by) burning calories to generate it"

[RonPurewal]

the parallel structures are "drawing" and "burning". the "by" is not part of the parallel structure.

[RonPurewal]

this whole thing is a non-issue, by the way, unless you have two parallel signals.

e.g.,
This animal lives in grass and trees. (correct sentence; grass || trees)
This animal lives in grass and in trees. (correct sentence; in grass || in trees)
^^ in these two sentences, the ONLY signal word is "and". so, the left-hand part is, basically, whatever is parallel to the right-hand part.

when there are TWO signals, then the parts FOLLOWING those signals must be parallel.
e.g.,
This animal lives in both grass and trees. (correct sentence; grass || trees)
This animal lives both in grass and in trees. (correct sentence; in grass || in trees)
but...
This animal lives in both grass and in trees. (incorrect; grass || in trees)
This animal lives both in grass and trees. (incorrect; in grass || trees)

[RonPurewal]

^^ so... if you had "either by drawing... or burning...", that'd be wrong.