文勇的新托福黄金&ccedil

abovethehorizonhowevertravelerstoantarcticahaverepeat

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Unformatted text preview: , what benefit do begging nestlings derive from their communications? One possibility is that a noisy baby bird provides accurate signals of its real hunger and good health, making it worthwhile for the listening parent to give it food in a nest where several other offspring are usually available to be fed. If this hypothesis is true, then it follows that nestlings should adjust the intensity of their signals in relation to the signals produced by their nestmates, who are competing for parental attention. When experimentally deprived baby robins are placed in a nest with normally fed siblings, the hungry nestlings beg more loudly than usual—but so do their better­fed siblings, though not as loudly as the hungrier birds. 8. The word derive in the passage is closest in meaning to ○ require ○ gain ○ use ○ produce Paragraph 4 在 Given that predators can make it costly to beg for food, what benefit do begging nestlings derive from their communications? One possibility is that a noisy baby bird provides accurate signals of its real hunger and good health, making it worthwhile for the listening parent to give it food in a nest where several other offspring are usually available to be fed. If this hypothesis is true, then it follows that nestlings should adjust the intensity of their signals in relation to the signals produced by their nestmates, who are competing for parental attention. When experimentally deprived baby robins are placed in a nest with normally fed siblings, the hungry 342 [email protected] 在在在在在在 www.liuwenyong.com 在在在在在在在在在在在在在在在,在在在在在在在在在在 nestlings beg more loudly than usual—but so do their better­fed siblings, though not as loudly as the hungrier birds. Paragraph 5 在 If parent birds use begging intensity to direct food to healthy offspring capable of vigorous begging, then parents should make food delivery decisions on the basis of their offsprings calls. Indeed, if you take baby tree swallows out of a nest for an hour feeding half the set and starving the other half, when the birds are replaced in the nest, the starved youngsters beg more loudly than the fed birds, and the parent birds feed the active beggars more than those who beg less vigorously. 9. In paragraphs 4 and 5, what evidence supports the claim that the intensity of nestling begging calls is a good indicator of which offspring in a nest would most benefit from a feeding? ○ When placed in a nest with hungry robins, wellfed robins did not beg for food. ○ Among robin nestlings, the intensity of begging decreased the more the nestlings were fed. ○ Hungry tree swallow nestlings begged louder than well­fed nestlings in the same nest. ○ Hungry tree swallow nestlings continued to beg loudly until they were fed whereas well­fed nestlings soon stopped begging. 10. It can be inferred from paragraphs 4 and 5 that parent songbirds normally do not feed ○ nestlings that are too weak to beg for food as vigorously as their nestmates ○ more than one hungry nestling during a single vi...
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This note was uploaded on 09/17/2013 for the course LANGUAGE 13DL208 taught by Professor Wang during the Fall '13 term at East China Normal University.

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