OG12-CR-49 关于E选项

kirbm

Certain genetically modified strains of maize produce a powerful natural insecticide. The
insecticide occurs throughout the plant, including its pollen. Maize pollen is dispersed by
the wind and frequently blows onto milkweed plants that grow near maize fields.
Caterpillars of monarch butterflies feed exclusively on milkweed leaves. When these
caterpillars are fed milkweed leaves dusted with pollen from modified maize plants, they
die. Therefore, by using genetically modified maize, farmers put monarch butterflies at
risk.
Which of the following would it be most useful to determine in order to evaluate the
argument?

C. Whether monarch butterfly caterpillars are actively feeding during the part of the
growing season when maize is releasing pollen

E. Whether any maize-eating insects compete with monarch caterpillars for the
leaves of milkweed plants growing near maize fields

E选项：其他insects与caterpillars争着吃maize。不就是evaluate “by using genetically modified maize, farmers put monarch butterflies at risk.”

如果insects争过了caterpillars，那么caterpillars没死
如果insects没争过caterpillars，那么caterpillars死

所以我选了E

钱多多

要注意题目中说的是这种蝴蝶只依靠milkweed的叶子生存，别的昆虫争不争夺，这种蝴蝶都会吃这种叶子，只要吃了就死。

kirbm

要注意题目中说的是这种蝴蝶只依靠milkweed的叶子生存，别的昆虫争不争夺，这种蝴蝶都会吃这种叶子，只要吃了就死。

-- by 会员 钱多多 (2012/1/14 21:32:23)

那这样说的话蝴蝶的毛虫没有争过别的昆虫，蝴蝶的毛虫是饿死的，而不是maize的作用
好像有点混乱了。。。

钱多多

应该不会出现其他昆虫密密麻麻占据了所有的叶子，蝴蝶一口也吃不到的情况。。。争不争得过只是相对的，不能太极端。我们只讨论蝴蝶是否处在被杀死的危险中，只要有可能吃到叶子，那么它们就处在这种危险当中。c选项就很好的解释了这一点，因为在不授粉的季节不会有花粉传播，蝴蝶也根本接触不到，就没有危险。

kirbm

我还是新手，问得问题都不在路子上。。

谢谢你的解答。