Experts have differences over how tarantulas make silk come out of the

OFFICIAL EXPLANATION






• Meaning?
Experts disagree about the way tarantulas emit silk from their feet so that they can maintain their grip on steep, slippery surfaces.


• Split #1: to express purpose, use the infinitive

The tarantulas emit silk from their feet for a purpose: to maintain their grip on steep, slippery surfaces.

Options A, B, and E incorrectly use for maintaining to describe this purpose.
In order to describe purpose, for maintaining should be expressed in the infinitive form to maintain.
→ correct: The conductor turned her left hand palm down [in order] to maintain the orchestra's smooth sound.
→ wrong: The conductor turned her left hand palm down for maintaining the orchestra's smooth sound.

Eliminate A, B, and E

• Split #2: diction and concision

Meaning
Whatever these enormous spiders do, it is weird.
That said, compare option C to option D

In (C), the tarantulas are able to create silk with their feet.
In (D), the tarantulas emit silk from their feet.

Option D is shorter and crisper than C—and more sensible, I think.
→ We do not have to be entomologists to sense that the spiders do not create the silk with their feet but rather let the silk out from (emit from) their feet in order to avoid slipping.

Concision is really a thing.
From (C), delete are able to. Result? Tarantulas create silk . . . .
If you can delete words and convey the same meaning, then the words are unnecessary and OG writers will call the option "wordy."
Option C is wordy.

Option C is also a bit redundant.
In the non-underlined portion, how makes the use of are able to (= can) largely redundant.
How (by what means) implies can.

Finally, although the phrase differ as to how in (C) is not wrong, the phrase is both rarely used and adds a somewhat formal layer intended to convey "with respect to."

Option D is better than option C.
Eliminate C

• other issues

Options C and D use a more effective verb than do the other three options; both (C) and (D) use differ.
As I have mentioned before, strong verbs drive good prose in English.
→ helping verbs such as have often dilute the strength of a verb
→ the only way to absorb this sense about verbs is to read good prose.

Options A and B are examples of what OE writers would call "wordy":
→ Option A uses have differences
→ Option B uses have differing opinions
This way is better: Experts differ.

Option E is an example of what OE writers would call wordy and awkward:
Option E uses disagree over the abilities of.

The answer is D.

COMMENTS

awichal , Fighter1095 , and dinesh2392 , welcome to SC Butler.

tyildirim92 , who has an interview with one of his target schools (who had? I am time zone confused) -- I wish you luck.

For those of you who mentioned that to maintain expresses purpose whereas for maintaining does not: well done.
The best way to express purpose in English is to use the infinitive or a phrase such as so that.
These concepts are fairly basic and simple—and they are tested frequently by GMAC, though aspirants sometimes do not notice that fact.

These next comments do not apply to a few of you, who acquitted yourselves well.

When you write an answer, I much prefer an explanation to an assertion.
Try to remember when you first started studying SC. People in that situation are your audience.

(Well, I'm your audience, too, so practice writing a good sentence now and then. )

Suppose that a sentence were to contain a truly ambiguous pronoun, one that could logically refer to more than one antecedent.
Suppose that I were to write: ambiguous pronoun
Suppose that an aspirant in the first stage of study were to read my answer.
Is that person helped by the labeling?
Well, yes, to some degree. She is on notice that they must refer clearly to something.

But I could be more effective (and hence train my own brain more effectively) if I were to write,
The pronoun they could logically refer either to monkeys or panda bears and is therefore ambiguous.

Because I can, I'm giving kudos to everyone.