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标题: GMAT-22-33请教求解思路 [打印本页]

作者: sv2000 时间: 2005-11-11 14:26
标题: GMAT-22-33请教求解思路

In order to withstand tidal currents, juvenile horseshoe crabs frequently burrow in the sand. Such burrowing discourages barnacles from clinging to their shells. When fully grown, however, the crabs can readily withstand tidal currents without burrowing, and thus they acquire substantial populations of barnacles. Surprisingly, in areas where tidal currents are very weak, juvenile horseshoe crabs are found not to have significant barnacle populations, even though they seldom burrow.

Which of the following, if true, most helps to explain the surprising finding?

Tidal currents do not themselves dislodge barnacles from the shells of horseshoe crabs.

Barnacles most readily attach themselves to horseshoe crabs in areas where tidal currents are weakest.

The strength of the tidal currents in a given location varies widely over the course of a day.

A very large barnacle population can significantly decrease the ability of a horseshoe crab to find food.

Until they are fully grown, horseshoe crabs shed their shells and grow new ones several times a year.

作者: yangsh 时间: 2005-11-11 16:08
E

作者: williamweizh 时间: 2005-11-12 04:38

该题为EXPLAIN.

前提:年轻的蟹挖洞,成年的时候不挖,所以有大量的BARNACLE

现象:年轻的蟹不挖洞,却没有BARNACLE

我的第一反应是年轻的蟹吸引不了BARNACLE,看了答案,只有E说蟹长大了换壳,所以选E

作者: sv2000 时间: 2005-11-12 15:41
还是不太理解啊？

作者: 不知不觉 时间: 2005-11-12 23:16

如果潮汐弱的话,蟹壳上会有很多B,但是现在的现实就是没有想象中那么多B, 因为中间曾经换了几次壳,每次换壳就把爬满B的壳换掉了,新长出来的是没有B的,所以现在看到的成年蟹上面没有很多B,因为新洗好澡新换好衣服,当然身上没多少虱子跳蚤什么的.

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