Dung beetles attach themselves to herbivores

Hey,

Can someone please explain why "waiting" is more suitable than "wait"?

Thanks!

Dung beetles attach themselves to herbivores, ----.

(B) waiting for their dung to drop, and after capturing it, roll the dung, following a
straight line in spite of all obstacles, and bury it either for food storage or for making
a brooding ball.

(C) wait for their dung to drop, and capture it, roll the dung, following a straight line in
spite of all obstacles, and bury it either for food storage or for making a brooding
ball.

-ing forms provide an explanation for the previous sentence or phrase. In this sentence it is difficult to say which is an explanation and which an item in a row.

But only in C there is no "after", which changes the meaning. The intended meaning in the original sentence should not be changed. So I'd go for B.

Dung beetles attach themselves to herbivores, waiting for their dung to drop, and after capturing it, roll the dung, following a straight line in spite of all obstacles, and bury it either for food storage or making a brooding ball.

This question requires you to understand the main verbs/actions and subordinate actions in the sentence. This will help you determine whether to use a verb or a verb+ing modifier/participle and identify the correct parallel structure.

There are 2 sets of actions: the dung beetle attaches itself to herbivores and wait for
them to drop dung; in the second stage, after capturing the dung, the beetle rolls the
dung (following a straight line) and buries it for food or to make a brooding ball.
The subordinate actions must be in participial form - waiting, capturing, following.
The others must be in present tense and parallel to each other. Secondly, either for X
or for Y' is the right idiom.

Dung beetles (subject) attach (main verb) themselves to herbivores, waiting (participle) for their dung to drop, and after capturing (participle) it, roll (verb) the dung, following (participle) a straight line in spite of all obstacles, and bury (verb) it either for food storage or for making a brooding ball.

(A) waiting for their dung to drop, and after capturing it, roll the dung, following a straight line in spite of all obstacles, and bury it either for food storage or making a brooding ball.
A uses the idiom either for X or Y - incorrect. Eliminate

(B) waiting for their dung to drop, and after capturing it, roll the dung, following a straight line in spite of all obstacles, and bury it either for food storage or for making a brooding ball.
This option is parallel with the usage of the idiom and hence is correct.

(C) wait for their dung to drop, and capture it, roll the dung, following a straight line in spite of all obstacles, and bury it either for food storage or for making a brooding ball.
And' before ‘capture' is not necessary and destroys parallelism. Eliminate.

(D) wait for their dung to drop, and after capturing it, roll the dung, following a straight line in spite of all obstacles, and bury it either for food storage or making a brooding ball.
uses the incorrect idiom either for X or Y'. Eliminate.

(E) wait for their dung to drop, and after capturing it, roll the dung, follow a straight line in spite of all obstacles, burying it either for food storage or for making a brooding ball.
The use of ‘follow' is incorrect as it is an action subordinate to the act of rolling the
dung and must be in participial form; if ‘follow' is to be used, it must be preceded by
‘and'. Eliminate

VP
GMAT SME

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