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题目材料:
Many tadpoles live in temporary ponds-ponds that dry up for part of each year. When the dry season comes, those tadpoles that have not yet developed into frogs die. A tadpole can only develop rapidly if it spends much of its time feeding, generally by scraping food off decaying leaves. Nevertheless, those tadpoles in a temporary pond that spend the most time feeding have relatively poor chances of developing into frogs.
Which of the following, if true, most helps to explain the poor survival rate of the tadpoles that spend the greatest amount of time feeding?
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AThe animals that eat tadpoles in temporary ponds tend to be much smaller than those that eat tadpoles in permanent ponds.
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BThe animals that eat tadpoles can only locate their prey when the tadpoles are moving.
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CSome ponds that support populations of tadpoles dry up in some years and not in others.
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DSome of the animals that prey on tadpoles in permanent ponds cannot survive in temporary ponds.
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EFrogs that as tadpoles grew up in temporary ponds do not survive to reproduce unless they can live for lona periods without a pond nearby.
B显示答案