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标题: 破解上的一题，真心不知道为什么选这个答案，求各位帮忙看一下 [打印本页]

作者: wjk 时间: 2011-7-18 10:40
标题: 破解上的一题，真心不知道为什么选这个答案，求各位帮忙看一下

On Pacific islands, a newly arrived gecko species, the house gecko, is displacing the previously established mourning gecko in urban areas, but populations of the two species are more stable in rural areas far from human settlement.The house gecko does not attack the mourning gecko, but in areas where insects congregate it prevents the mourning gecko from feeding on them.

Which of the following contributes most to an explanation of the difference between gecko populations in urban and rural areas?

(A) In urban areas, geckos are valued because they eat so many insects.

(B) Geckos defend territories against other members of the same species.

(D) In places where there are lighted buildings, insects tend to gather around the light.

(E) Mourning geckos are all females and reproduce asexually, but house geckos reproduce sexually.

答案：D

作者: balapupu 时间: 2011-7-18 14:57
是这样子滴，翻译如下：在PI这个地方呢，城市的H壁虎逐渐的取代了原来占主导地位的M壁虎，但是在农村，二者的数量变化比较平稳。H壁虎不袭击M壁虎，但是在昆虫聚集在一起的地方，M壁虎无法以昆虫为食。注意这里需要搭桥，即虫子聚集和壁虎地区分布的关系，即用后者解释前者，所以有选项D，有光的地方，虫子会聚集，所以这很合理的解释了农村和城市的差距，因为城市灯光多，虫子聚集，M壁虎无法获取食物所以饿死了，所以相对H壁虎占了主导地位。

作者: wjk 时间: 2011-7-18 16:11
原来是这样啊，明白了自己做的时候好难想明白啊谢谢

作者: Shine61 时间: 2011-8-11 21:01
balapupu解释得很透彻，明白了

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