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题库 / GMATLA-CR-132
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?
No other food available to the birds on Delaware's beaches is as nutritious and accessible as are crab eggs.
The decline in the number of crabs on Delaware's beaches is due to the harvesting of crabs by humans.
There are more crabs on Delaware's beaches than in any other area that the migrating birds pass through.
The crabs do not conceal their eggs.
The earlier in the season the shorebirds complete their migration, the more likely they are to breed successfully.
要读懂结论虽然说鸟内不会因为crab数量减少影响，背后原因是因为只要鸟待得够久他还是可以吃到足够的crab，选项E削弱了这个结论，因为如果鸟待太久，就会降低成功繁殖的概率，而数量有可能下降
conclusion: 鸟的数量不会因为螃蟹少了而下降
相关因果 其他原因导致
文中结论是 不会对shorebird的population有影响 答案e很明显 削弱了这个结论 这道题主要还是照结论的问题 容易混淆 但是后面的冒号明显是解释的内容 属于P
这题是果因推理吧？前提：crab declined，but poses no threat to bird。结论：birds remain longer could eat enough eggs to complete migration