求NN解答一道OG13中的题目！！

kittyljy

Which of the following most logicallycompletes the argument?

By competing with rodents for seeds, blackants help control rodent populations that pose a public health risk. However, avery aggressive species of black ant, the Loma ant, which has recently invadeda certain region, has a venomous sting that is often fatal to humans. Therefore,the planned introduction into that region of ant flies, which prey on Lomaants, would benefit public health, since.

(A) ant flies do not attack blackants other than Loma ants

(B) Loma ants are less effectivethan many bird species in competing with rodents for seeds

(C)  certain other species of blackants are more effective than ants in competing with rodents for seeds

(D)the sting of Loma ants can alsobe fatal to rodents

(E)   some pesticides that could beused to control Loma ants are harmful to the environment

为什么选A？？？疑惑！！！！

Valenski

首先分析A的正确性：  这个系统里一共有几个parts：（1）human  （2）rodent   （3）blackants   （4）blackants 的一种特殊种类-----Loma    （5）ant flies              2对1不好  3对2不好   4对1不好    而5对4不好     所以可见要消除2和4而不能对3和1造成威胁     所以答案为A------5既可以消除4而又不至于威胁3   从而3能帮助消除2   最后人类是最终赢家。      感觉这道题还是蛮简单的

Valenski

不知道LZ错选了哪个答案  我帮你解释