[求助]xdf-193,此种题总是错/大全-16-1

happysara

The chanterelle, a type of wild mushroom, arows beneath host trees such as the Douglas fir, which provide it with necessary sugars. The underground filaments of chanterelles, which extract the sugars, in turn provide nutrients and water for their hosts. Because of this mutually beneficial relationhip, harvesting the chanterelles growing beneath a Douglas fir seriously endangers the tree.

which of the following, if ture, casts the most doubt on the conclusion drawn above?

A  the number of wild mushrooms harvested has increased in recent years.

B  chanterelles grow not only beneath douglas firs but also beneath other host trees

C  many types of  wild mushrooms are found only in forests and cannot easily be grown elsewhere

D the harvesting of wild mushrooms stimulates future growth of those mushrooms

E young douglas fir seedlings die without the nutrients and water provided by chanterelle filaments

the answer is d, why??

这种题目我总是转不过弯来，到底应该怎么理解？？

leeon

Reasoning of the passage:

chanterelles provide nutrients and water for their hosts-->harvesting the chanterelles endangers the tree.

D said the harvesting of wild mushrooms stimulates future growth of those mushrooms, that is, harvesting the chanterelles will not endanger the tree.

Thus D weakens the conclusion of the paragraph.

leeon

The answer D is vague to choose at first glance, but u can pick it out by ruling out other choices, A, B and C are irrelevant choices, E supports the conclusion.