请帮忙哟~~~

pandaeyes

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?

 

1. 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.(。。。Bbird不吃budworm,所以budworm的减少与之无关，不能说明budworm的减少一定与Tbird的减少有关啊。。。)
2. The spruce-budworm population has dropped because of a disease that can infect budworms but not Tennessee warblers.
3. The drop in the population of the spruce budworm is expected to be only temporary.
4. Many Tennessee warbler have begun migrating in the fall to places other than traditional coffee plantations.
5. Although many North American songbirds have declined in numbers, no other species has experienced as great a decline as has the Tennessee warbler.

答案是A...

julianfl

http://forum.chasedream.com/dispbbs.asp?BoardID=24&ID=64928

以后希望MM可以把题号写在帖子标题中，这样便于大家讨论，方便别人查询。

谢谢：）