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标题: prep 11-the answer contradicts with that of OG! [打印本页]

作者: shinycrystal    时间: 2007-4-24 14:53
标题: prep 11-the answer contradicts with that of OG!

prep 11 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.

Here the answer is C,while OG says the answer is B...

I'd like to hear your opinions!


作者: gonghao    时间: 2007-4-24 16:28

stands with OG

two options for you to choose either of them.

First: can't keep balance

Second: Can't process the rapidly changing visual information that will cause blind.

B: says it could keep balance but processing rapidly changing visual information so it has to  equally stop frequently to get a clear environment situation.

C:[The beetles maintain a fixed time interval between pauses] It's hard to say this is beacuse it could not keep the balance or can't keep processing after a fixed time while preying an insect. Maybe it is so tired or exhausted after such interval pursuit.

I think C could explain both of two options or could explainable in other conditions.  


作者: Prison_Break    时间: 2007-4-24 17:30
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.----B is correct
作者: shinycrystal    时间: 2007-4-25 09:15

I agree,the answer should be B!

thanks!


作者: snowofjune    时间: 2007-12-14 12:14
up
作者: embrace1986    时间: 2008-1-12 21:40
我支持C。原文说一种观点认为是因为速度太快控制不了所以停一下,另一种说眼睛看到东西动得太快接受不了所以停下。C说停一下以后能用更快的速度飞,所以不是控制不了速度,削弱了第一种说法。




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