帮忙看一道gwd答案不一致的题吧。。拜托了。。

28. GWD28-Q28:

Which of the following most logically completes the argument?

A certain cultivated herb is one of a group of closely related plants that thrive in soil with high concentrations of metals that are toxic to most other plants.  Agronomists studying the herb have discovered that it produces large amounts of histidine, an amino acid that, in test-tube solutions, renders these metals chemically inert.  Possibly, therefore, the herb’s high histidine production is what allows it to grow in metal-rich soils, a hypothesis that would gain support if ______.

E.        the concentration of histidine in the growing herb declines as the plant approaches maturity

GWD 答案不一样。。有c 有e...........我觉得应该选c  。。。不知各位大牛的高见如何。。。。

题目说在实验室中（in test-tube)可以证明histidine使得小草在metal rich soil中生长,如果假设这个就是小草的原因，那么需要有什么支持？

E说小草在生长过程中体内含有histidine，是想说实验室的结论可以由现实中的小草的生长来证实。

C说其他的这种小草体内也有histidine。但是没有表示出“结论由实践检验得出”的意思。

不过我做这个题的时候也选的c。呵呵。

哦哦。。。大概明白了。。。谢谢啊牛！！！