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标题: [讨论]GWD-3-38 [打印本页]

作者: jackychew    时间: 2005-4-7 00:50
标题: [讨论]GWD-3-38

Q38:


Kate:  The recent decline in numbers of the Tennessee warbler, a North American songbird that migrates each fall to coffee plantations in South America, is due to the elimination of the dense tree cover that formerly was a feature of most South American coffee plantations.



Scott:  The population of the spruce budworm, the warbler’s favorite prey in North America, has been dropping.  This is a more likely explanation of the warbler’s decline.



Which of the following, if true, most seriously calls Scott’s hypothesis into question?




  • The numbers of the Baltimore oriole, a songbird that dose not eat budworms but is as dependent on South American coffee plantations as is the Tennessee warbler, are declining.

  • The spruce-budworm population has dropped because of a disease that can infect budworms but not Tennessee warblers.

  • The drop in the population of the spruce budworm is expected to be only temporary.

  • Many Tennessee warbler have begun migrating in the fall to places other than traditional coffee plantations.

  • Although many North American songbirds have declined in numbers, no other species has experienced as great a decline as has the Tennessee warbler.

  • 作者: jackychew    时间: 2005-4-7 00:51
    大案为A,选对了。但在复看时觉得B很具迷惑性,请点播,谢谢。
    作者: jimjohn    时间: 2005-4-7 02:55
    Whenever spruce-budworm  population droped, the argument of Scott is supported.




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