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When a caterpillar emerges from the egg on a tree branch, it immediately climbs upward until it finds a leaf bud to eat. Biologists thought that this behavior displayed an innate tendency to move in the direction opposite to the pull of gravity. In a recent experiment, a strong light source was placed at the bottom of a tree, and caterpillars, after hatching, climbed downward.

Which of the following hypotheses is best supported by the statements given?

正确答案: C

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[求助]prep1-33

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楼主
发表于 2009-10-10 10:29:00 | 只看该作者

[求助]prep1-33

(31934-!-item-!-188;#058&005658)

 

When a caterpillar emerges from the egg on a tree branch, it immediately climbs upward until it finds a leaf bud to eat.  Biologists thought that this behavior displayed an innate tendency to move in the direction opposite to the pull of gravity.  In a recent experiment, a strong light source was placed at the bottom of a tree, and caterpillars, after hatching, climbed downward.

 

Which of the following hypotheses is best supported by the statements given?

 

(A) Caterpillars have an innate tendency to move in the direction of gravity.

(B) Newly hatched caterpillars are unable to see in the dark.

(C) Newly hatched caterpillars move towards the strongest light source in the environment.

(D) Newly hatched caterpillars move toward the leaf bud nearest to them.

(E) The eyes of newly hatched caterpillars become less sensitive to light over time.

 

答案是C   我选择A,为什么不对呢?? 

大家帮忙解释一下吧!!

沙发
发表于 2009-10-10 11:33:00 | 只看该作者

开始它是往上,往引力相反的方向

后来下面有光了,它就往有光的地方走了,也就是引力相反的方向

C比较正确吧

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