moths and predators

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moths and predators

by kobel51 » Mon Jan 27, 2014 8:37 am
Which of the following most logically completes the passage?

Each species of moth has an optimal body temperature for effective flight, and when air temperatures fall much below that temperature, the moths typically have to remain inactive on vegetation for extended periods, leaving them highly vulnerable to predators. In general, larger moths can fly faster than smaller ones and hence have a better chance of evading flying predators, but they also have higher optimal body temperatures, which explains why __________.

(A) large moths are generally able to maneuver better in flight than smaller moths

(B) large moths are proportionally much more common in warm climates than in cool climates

(C) small moths are more likely than large moths to be effectively camouflaged while on vegetation

(D) large moths typically have wings that are larger in proportion to their body size than smaller moths do

(E) most predators of moths prey not only on several different species of moth but also on various species of other insects
Source: — Critical Reasoning |

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by Patrick_GMATFix » Mon Jan 27, 2014 8:56 am
All fill-in-the-blanks require you to complete a thought the author has begun. In this case, what goes in the blank is the result of the phenomenon described.
Rephrase: Large moths typically fly faster so they can evade predators better, BUT they need a higher temperature to fly so ______. The right answer must conclude that in lower temperatures, small moths actually have a better chance at evading predators.

The full solution below is taken from the GMATFix App.

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by [email protected] » Mon Jan 27, 2014 1:45 pm
Hi kobel51,

This CR prompt is an example of a fill-in-the-blank inference question. The correct answer will complete the "thought" in the last sentence and will logically match the other information presented by the prompt.

Here's what the prompt tells us:
-Each species of moth has an optimal body temperature for flight; when temperatures FALL much below that temperature, moths have to stay inactive on vegetation (meaning the moths can't fly), leaving the moths vulnerable to predators.
-Larger moths generally fly faster than smaller ones; this provides a better chance to avoid predators.
-Larger moths have a higher optimal body temperature, which explains.......WHAT???

Using the information above, we need an answer that tells us something about larger moths and involve the fact that larger moths have a higher optimal body temperature. The higher optimal body temperature means that larger moths have a higher "range" of temperatures in which they wouldn't be able to fly (and thus be vulnerable to predators) than smaller moths.

Only answer B makes sense. In a warmer climate, larger moths would be able to fly (and fly faster to avoid predators) than in cooler climates (in which they couldn't fly and would be vulnerable).

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