replying to a private message by our quant expert who wants a full immersion explanation of this tiny but nasty passage here we go rx10


Although it is intuitively clear that an increase in antipredator behavior lowers an animal’s risk of predation when predators are present, such benefits are not easily demonstrated.

Even though it is intuitively clear

These few words look superfluous but instead, they are crucial to the whole passage. They mean the following;

through observation or empiric study is clear something but ..........

a certain type of behaving by animal X could be or not useful against the predators but this is NOT demonstrated yet



One study that did so found that well-fed guppies are more alert for predators and are consequently less likely to be killed than are their hungry counterparts, which feed with greater intensity.

The well-fed guppies are more prone and steady to react in front of a predator than their hungry counterparts

It is also well documented that a decrease in activity lowers an animal’s risk of predation by reducing the probability of being detected or encountered by a predator.

The fewer movements an animal has the higher is the probability of being predated. This also could be useful in conjunction with the fact that the well-fed guppies are killed less than those animal that are hungry

Mmmmhhh convoluted concept

This effect was convincingly demonstrated by a study in which it was found that partially anesthetized tadpoles were less likely to be captured by dragonfly larvae than were unanesthetized tadpoles.


This is just an example to show the discovery above



1) It can be inferred that the guppy study and the tadpole study, as they are described in the passage, differed in which of the following ways?

The animals less likely to become the victims of predators were the more active ones in the guppy study but were the less active ones in the tadpole study.

this cannot be true for two reasons: first of all, the guppies were more alert and NOT active which is quite different.
Secondly, also the tadpoles were less active. See the last sentence of the passage, at least partially

The animals less likely to become the victims of predators were those more alert to their surroundings in the guppy study but were the less alert ones in the tadpole study.


This is true: alert the first ones and partially with anesthesia the second ones

The situation created experimentally for the guppy study would be more likely to occur in the wild than would the situation created for the tadpole study.

This is also true see my very first words that I said are soooooooooo important

B and C are the correct choices



2) In the context indicated, “demonstrated” most nearly means

A) explained
B) presented
C) shown
D) protested
E) justified

C straight. Not so many comments on this I have.

if someone does not nail this question in 3 seconds then he/she has a lottttt of troubles on the GRE