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 ______.
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这道题争议很大,选A,C,D,E的都有,但支持A的人最少,不过我看到一个支持A的MM强调了一些信息,让我觉得A或者确实是正确答案,请大家再来讨论讨论.
结论是最关键的:the herb’s high histidine production is what allows it to grow in metal-rich soils
我们不能忽略这个单词high,我觉得high histidine和histidine是有区别的,如果读出结论真正强调的东西是这种草的high histidine production是它存活的关键,那么答案就是A.
open to discuss
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