请教og12th逻辑评价题

didi0910

Certain genetically modifi ed 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 fi elds.
Caterpillars of monarch butterfl ies feed exclusively
on milkweed leaves. When these caterpillars are
fed milkweed leaves dusted with pollen from modifi ed
maize plants, they die. Therefore, by using genetically
modifi ed maize, farmers put monarch butterfl ies at risk.
Which of the following would it be most useful to
determine in order to evaluate the argument?
(A) Whether the natural insecticide is as effective
against maize-eating insects as commercial
insecticides typically used on maize are
(B) Whether the pollen of genetically modifi ed maize
contains as much insecticide as other parts of
these plants
(C) Whether monarch butterfl y caterpillars are
actively feeding during the part of the growing
season when maize is releasing pollen
(D) Whether insects that feed on genetically
modifi ed maize plants are likely to be killed by
insecticide from the plant’s pollen
(E) Whether any maize-eating insects compete with
monarch caterpillars for the leaves of milkweed
plants growing near maize fi elds
感谢！！！

didi0910

首先梳理题目条件：

　　(1)有一种经过基因改良的玉米，可以产生一种杀虫成分来抵御虫子。而且这种成分在这种玉米的全身上下各部分都有，连花粉都有

　　(2)这种玉米的花粉会被风吹到玉米田旁边的植物上，然后有一种M蝴蝶的幼虫是以该植物的叶子为食的

　　(3)在实验室里，喂食沾有转基因玉米花粉的植物叶子的M蝴蝶幼虫都死了

　　题目中心论点：这种转基因玉米的使用会无意中危及M蝴蝶

　　A.Per unit of volume, the natural insecticide produced by the genetically modified maize plants is less toxic to insects than are many commercial insecticides commonly used on maize plants.

　　本选项说同样的量玉米的杀虫剂比商用的杀虫剂毒性弱，属于上面所述的转移焦点(转移焦点至题干可能提及，或未曾提及之事物)，与题目论点——玉米会杀M幼虫无关

　　B.Standard weed-control practices that have been used by farmers for decades have largely eliminated milkweed plants from certain areas where monarch-butterfly caterpillars were once common.

　　本选项说由于控制杂草milkweed在这个地区减少了很多，所以虫子也不剩多少了，同样属于转移焦点，与题目论点无关。

　　C.The experiments showed that the caterpillars were not harmed by contact with the pollen from the genetically modified plants unless they ingested it.

　　本选项说M幼虫只要不吃花粉就不会死，除此之外爱怎么接触怎么接触，总之就是死不了;说到吃花粉会死，那也就还是玉米会危及M幼虫，支持了结论。但是题目求的是weaken，所以错误啦。

　　D.The maize-eating insects that the natural insecticide protects against do not feed on the pollen of the maize plant.

　　本选项说吃玉米的虫子不会吃花粉，还是转移焦点，无关题目结论。

　　E.Airborne maize pollen tends to collect on the middle leaves of milkweed plants and monarch caterpillars feed only on the plant’s tender upper leaves.

　　正解。本选项说花粉会落在中间的叶子上，而M幼虫只会吃上面的叶子，总之一句话，随你怎么飘，就是不吃你。这样一来，虽然玉米花粉飘到milkweed上了，但是M幼虫既没有接触到花粉也没有吃，所以完全不会威胁到生存，也就是否定了题目的果——因果关系中的结果不会产生，故而削
这个某个网站解释~我直接晕掉了~答案明明是c啦~~~求解释，辛苦辛苦！