GMAT考题：OG2016-CR-86

GMAT考题

题库 / OG2016-CR-86

Scientists have modified feed corn genetically, increasing its resistance to insect pests. Farmers who tried out the genetically modified corn last season applied less insecticide to their corn fields and still got yields comparable to those they would have gotten with ordinary corn. Ordinary corn seed, however, costs less, and what these farmers saved on insecticide rarely exceeded their extra costs for seed. Therefore, for most feed-corn farmers, switching to genetically modified seed would be unlikely to increase profits.

Which of the following would it be most useful to know in order to evaluate the argument?

Whether there are insect pests that sometimes reduce feed-corn yields, but against which commonly used insecticides and the genetic modification are equally ineffective

Whether the price that farmers receive for feed corn has remained steady over the past few years

Whether the insecticides typically used on feed corn tend to be more expensive than insecticides typically used on other crops

Whether most of the farmers who tried the genetically modified corn last season applied more insecticide than was actually necessary

Whether, for most farmers who plant feed corn, it is their most profitable crop

考题讲解

毕出

情景：科学家改变了玉米的基因，增加了其对害虫的抵抗。农民上个季节种转基因玉米减少了杀虫剂，但是产量跟普通玉米一样。因为普通玉米种子便宜，转基因玉米在杀虫剂上节约的钱不能抵消高额的种子成本，所以种转基因玉米不能增加利润。

推理：本题的前提和结论讲的是两件事，并且结论为果，所以为因果推理。
顺序的因果逻辑：因为普通玉米种子便宜，转基因玉米在杀虫剂上节约的钱不能抵消高额的种子成本，所以种转基因玉米不能增加利润
（因）前提：普通玉米种子便宜，转基因玉米在杀虫剂上节约的钱不能抵消高额的种子成本
（果）结论：种转基因玉米不能增加利润

选题方式：因果推理只有一个评估方向，简而言之，即，需要反驳结论。

选项分析：

A选项：是否有某些时候影响玉米地的收成但是用杀虫剂和转基因玉米都没有效果的害虫？本选项和推理文段的结论无关。

B选项：在过去几年玉米的价格是否稳定？玉米价格包含了转基因和不转基因，所以本选项不能反驳结论（只说转基因的事情）。

C选项：玉米的杀虫剂是否比其他作物的杀虫剂便宜？本选项讨论的是玉米和其它作物的比较，而推理文段的结论比较的是转基因和不转基因，所以本选项和结论无关。

D选项：Correct. 上个季节种转基因玉米的农民洒的农药是否比实际需要更多？如果农药洒多了，则其表示正常洒农药会减少成本，自然增加了利润。

E选项：对于种玉米的农民来说，玉米是否是利润最高的作物？本选项讨论的是玉米和其它作物的比较，而推理文段的结论比较的是转基因和不转基因，所以本选项和结论无关。