xdjms, please advise on the follow one which appears on Prep. the answer is C.
24. (29155-!-item-!-188;#058&003857)
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.
i'm confused about this too. i found this on an American website
"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.
"usually respond immediately to changes" implies beetle does not become blind so refuting the second hypothesis. "pause equally frequently whether..." implies irrespective of condition they stop, so "rest" is not the issue, as if it is an issue then going up incline they will rest more frequently.
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 the next pause.
"maintain a fixed time interval..." refutes first experiment. "though when an insect..." supports beetle is not able to see it when prey started fleeing, so next time when beetle pauses and see prey is fleeing increases its speed.
maybe it's helpful
选b吧，可以立马根据猎物改变方向，但是仍然interval停下来。
A, could indicate TB doesn`t need interval stop, however meanwhile it does not indicate TB has visual issues when running.
C,when running, TB could change speed according to actions of preys. but it does not weak the Hyp that TB need interval stop during running.
D,out of scope
E,out of scope, only mentions the visual capicity and reaction of TB.
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