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CAT 2017 Slot 2 — VARC Question 25

Main Point IdentificationEasy

The passage given below is followed by four summaries. Choose the option that best captures the author’s position.

North American walnut sphinx moth caterpillars (Amorpha juglandis ) look like easy meals for birds, but they have a trick up their sleeves- they produce whistles that sound like bird alarm calls, scaring potential predators away. At first, scientists suspected birds were simply started by the loud noise. But a new study suggests a more sophisticated mechanism the caterpillar’s whistle appears to mimic a bird alarm call, sending avian predators scrambling for cover. When pecked by a bird, the caterpillars whistle by compressing their bodies like an accordion and forcing air out through specialized holes in their sides. The whistles are impressively loud-they have been measured at over 80 dB from 5cm away from the caterpillar-considering they are made by a two-inch long insect.

Answer & solution

Correct answer: North American walnut sphinx moth caterpillars, in a case of acoustic deception, produce whistles that mimic bird alarm calls to defend themselves.

  • A

    North American walnut sphinx moth caterpillars will whistle periodically to ward off predator birds-they have a specialized vocal tract that helps them whistle

  • B

    North American walnut sphinx moth caterpillars can whistle very loudly; the loudness of their whistles is shocking as they are very small insects.

  • North American walnut sphinx moth caterpillars, in a case of acoustic deception, produce whistles that mimic bird alarm calls to defend themselves.

  • D

    North American walnut sphinx moth caterpillars, in a case of deception and camouflage, produce whistles that mimic bird alarm calls to defend themselves.

Solution

Easy

This is a para-summary question. Nail the central idea of the paragraph, then pick the option that preserves it without distorting, adding, or omitting. The core here has two parts: (i) the caterpillars whistle to scare birds, and (ii) the new finding is that the whistle is not just a startling noise but a mimicry of a bird alarm call — a case of acoustic deception.

A

Option 1 — Omits the key idea. It says the caterpillars whistle "periodically" using a "specialized vocal tract." The paragraph says they whistle when pecked by a bird (a defence response, not periodic), and the crucial point — that the whistle mimics a bird alarm call — is dropped entirely. Eliminate.

B

Option 2 — Captures only a minor detail. It focuses solely on the loudness of the whistle (the 80 dB aside). That is a supporting detail, not the main finding. The central "mimics a bird alarm call to deceive predators" idea is missing. Eliminate.

C

Option 3 — Correct. It states the caterpillars produce whistles that mimic bird alarm calls to defend themselves, and labels this an "acoustic deception." This is exactly the sophisticated mechanism the new study proposes. Retain.

D

Option 4 — Adds an unsupported idea. It is almost identical to option 3 but inserts "camouflage." The paragraph describes only acoustic (sound-based) deception; there is no visual hiding or camouflage. This added word makes it inaccurate. Eliminate.

The summary that best captures the author's position is option 3: the caterpillars, in a case of acoustic deception, produce whistles that mimic bird alarm calls to defend themselves.

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CAT 2017 Slot 2 VARC Q25: The passage given below is followed by four summaries. Choose the option that best captures the author’s — Solution | TheCATExam