Critical Reasoning

This is from GMATPREP001:

Tiger beetles are such fast runners that they can capture virtually any nonflying insect. However, when running toward an insect, the beetles intermittently stop, and then, a moment later, resume their attack. Perhaps they cannot maintain their pace and must pause for a moment's rest; but an alternative hypothesis is that while running tiger beetles are unable to process the resulting rapidly changing visual information, and so quickly go blind and stop.

Which of the following, if discovered in experiments using artificially moved prey insects, would support one of the two hypotheses and undermine the other?

(A) When a prey insect is moved directly toward a beetle that has been chasing it, the beetle immediately turns and runs away without its usual intermittent stopping.
(B) In pursuing a moving insect, the beetles usually respond immediately to changes in the insect's direction, and pause equally frequently whether the chase is up or down an incline.
(C) The beetles maintain a fixed time interval between pauses, although when an insect that had been stationary begins to flee, the beetle increases its speed after its next pause.
(D) If, when a beetle pauses, it has not gained on the insect it is pursuing, the beetle generally ends its pursuit.
(E) When an obstacle is suddenly introduced just in front of running beetles, the beetles sometimes stop immediately, but they never respond by running around the barrier.

[spoiler]OA: C[/spoiler]

Answered B. Why is B wrong?

This is from OG12_Diagnostic Test:(Q25):

Tiger beetles are such fast runners that they can capture virtually any nonflying insect. However, when running toward an insect, a tigerbeetle will intermittently stop and then, a moment later, resume its attack. Perhaps the beetles cannot maintain their pace and must pause for a moment's rest; but an alternative hypothesis is that while running, tiger beetles are unable to adequately process the resulting rapidly changing visual information and so quickly go blind and stop.

Which of the following, if discovered in experiments using artificially moved prey insects, would support one of the two hypotheses and undermine the other?

A When a prey insect is moved directly toward a beetle that has been chasing it, the beetle immediately stops and runs away without its usual intermittent stopping.
B In pursuing a swerving insect, a beetle alters its course while running and its pauses become more frequent as the chase progresses.
C In pursuing a moving insect, a beetle usually responds immediately to changes in the insect's direction, and it pauses equally frequently whether the chase is up or down an incline.
D If, when a beetle pauses, it has not gained on the insect it is pursuing, the beetle generally ends its pursuit.
E The faster a beetle pursues an insect fleeing directly away from it, the more frequently the beetle stops.

[spoiler]OA: B[/spoiler]


Would any expert explain these two CR's in detail?

Thanks.

The difficulty here is that the answer has to confirm one hypothesis and deny the other. Paraphrasing:

hyp 1: they're tired

hyp 2: they've lost track of the prey

In the first version B is wrong because it confirms the "lost" hypothesis, but doesn't deny the "tired" hypothesis. They should stop more frequently running uphill than down.


C would deny the "tired" hypothesis because they are increasing speed after relocating hte prey.


For the second version you need C - the fact that pauses become more frequent supports the "tired" hypothesis and denies the "lost" one. If they are simply having trouble locating the prey, the pauses shouldn't become more frequent.