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OG11th 25: Tiger beetles are such fast runners that they can capture virtualy any nonflying insect. However, when running toward an insect, a tiger beetle will intermittently stop and then, a moment later, resume its attack. Perhaps the beetles cannot maintain their pace and must pause for 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 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 immidiately 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.
追跑时 (改变方向)代表视力很好 追时会停顿更频繁 所以代表目的是休息而非视力不好
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 beele pauses, it has not gained on the insect it is pursuing, the beetle generally ends its pursuit.
E. The faster a beetle pursues and insect fleeing directly away from it, the more frequently the beetle stops.
The answer is B
OG says: What point would strengthen one of the two hypotheses and weaken the other? Consider the information provided in each answer choice, remembering that information that supports one hypothesis must necessarily detract from the other. Any information that is not about pursuit or theat affects the two hypotheses equally may be dismissed from consideration. If the frequency of stopping increases when the beetle follows a swerving insect and must constantly change its course, then the second hypothesis is strengthened; the beetle's pauses increase as the variety of visual information that it needs to deal with increases.
B Correct. This statement provides information that stengthens the 2nd hypothesis: the swerving pursuit and the resulting continual course adjustments appear to be forcing the beetle to stop with increasing frequency to sort out the erratic visual information.
http://forum.chasedream.com/dispbbs.asp?BoardID=24&replyID=1391111&id=149684&skin=0 -------------------------------------------------------------------------------- 可是 注意一下OG11th 25的(C)答案是prep1-24的(B)
所以题目答案上和prep没有冲突? 以下是个人浅见还有参考其它帖子讨论之后整合一下结论 prep1-24 的(B)说明了
视力很好respond immediately to changes in the insect's direction 而且休息的频率很平均 whether the chase is up or down an incline
所以对于体力不支这假设没有进一步的weaken (C)则说明了在每停顿之间，维持了固定的时间区隔 虽然insect 维持不变的继续逃亡 但是beetles会在下一停顿之后加快速度追上 代表beetles 是因为体力不支而休息
如果是因为视力blind 而停下 若是加快速会更看不到 weaken 第二假设
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发表于 2007-5-30 10:07:00
