gwd-18-13

missgmat

Q13:

Eurasian watermilfoil, a weed not native to Frida Lake, has reproduced prolifically since being accidentally introduced there. In order to eliminate the weed, biologists proposed treating infested parts of the lake with a certain herbicide that is nontoxic for humans and aquatic animals. However, the herbicide might damage populations of certain rare plant species that the lake contains. For this reason local officials rejected the proposal.

Which of the following, if true, points out the most serious weakness in the officials¡¯ grounds for rejecting the biologists¡¯ proposal?

1 The continuing spread of Eurasian watermilfoil in Frida Lake threatens to choke out the lake¡¯s rare plant species.

2 Because of ecological conditions prevailing in its native habitat, Eurasian watermilfoil is not as dominant there as it is in Frida Lake.

3 The proliferation of Eurasian watermilfoil in Frida Lake has led to reductions in the populations of some species of aquatic animals.

4 Although Eurasian watermilfoil could be mechanically removed from Frida Lake, eliminating the weed would take far longer this way than it would using herbicides.

                    5 Unless Eurasian watermilfoil is completely eliminated from Frida Lake, it will quickly spread again once herbicide treatments or other control measures cease.

why choose A ?

rio

原文说用了除草剂不仅杀死W植物，还会杀死某种稀有植物。

A说如果不用除草剂，W植物疯狂泛滥也会把氧气耗尽，从而搞死该稀有植物。

xiaoniuren

DD