Q34:

During the month of May, crabs arrive on Delaware’s beaches to lay eggs.  Certain shorebirds depend on these eggs for food during their annual spring migration to their northern breeding grounds.  Delaware’s crab population has declined recently.  This decline, however, poses no serious threat to the migrating shorebird populations:  by remaining longer in Delaware, the birds will be able to eat enough crab eggs to allow them to complete their migration.

Which of the following, if true, most seriously weakens the argument?

1. No other food available to the birds on Delaware’s beaches is as nutritious and accessible as are crab eggs.
2. The decline in the number of crabs on Delaware’s beaches is due to the harvesting of crabs by humans.
3. There are more crabs on Delaware’s beaches than in any other area that the migrating birds pass through.
4. The crabs do not conceal their eggs.
5. The earlier in the season the shorebirds complete their migration, the more likely they are to breed successfully.

   百思不得其解   请NN帮忙

主要是看清结论是什么

题目说，carbs数量下降没有对鸟得数量造成影响，冒号后面给了一个解释。

E：鸟越早完成迁徙，越容易成功养育。

如果说：鸟在海滩上吃饱蛋再走得话，完成迁徙得时间就越长，则这样反而影响了鸟得数量。

我想题目给出的逻辑关系是：在D待得越久——吃到足够蛋——可以完成迁徙——

不会影响S数量

E选项：是越早完成迁徙——S成功生育

成功生育=不会影响S数量

果一致，但是因是相反的。。。所以削弱

欢迎指正