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 ______.
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.(惰性)  ossibly, therefore, the herb’s high histidine production is what allows it to grow in metal-rich soils, a hypothesis that would gain support if ______. A. histidine is found in all parts of the plant—roots, stem, leaves, and flowers B. the herb’s high level of histidine production is found to be associated with an unusually low level of production of other amino acids C. !others of the closely related group of plants are also found to produce histidine in large quantities D. cultivation of the herb in soil with high concentrations of the metals will, over an extended period, make the soil suitable for plants to which the metals are toxic E. the concentration of histidine in the growing herb declines as the plant approaches maturity 我选D,有人说选E,到底选哪个呢?大家讨论呀
第一直觉选D。看了大家的讨论后,似乎觉得选E。后来咨询了一位大牛,给出了这样的解释:本题缺少一个逻辑链,即inert=nontoxic。为了方便理解,还给出了个例子:学校长期受黑帮问题影响(concentrations of metal),现在学校引进了方法A(H)来消灭黑帮,但消灭黑帮后学生一定能学习好么?可能学校还有毒品问题。也就是说,inert metal不一定代表nontoxic,可能inert metal还有别的问题,D选项恰好弥补了这个问题,金属失活后,植物能很好成长。因此答案是D。
大家认真看一下题~ A certain cultivated herb is one of a group of closely related plants that thrive in soil with high concentrations of metals. 后面的thrive in soil with high concentrations 修饰的是 a group of closely related plant 文章说 a group 里的一种 herb 因为 histidine可以生长 ,得出(group 中的其他植物也是)因为H这种物质而得以生长,有gap!! 所以选C group 中的其他植物都有H这种物质 这样就可以推出是因为H物质。