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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
这是XDF蓝皮书上的一道题，蓝皮书给的答案是E；考近，做GWD给的答案是C。但是，我自己做的答案是D……
我的思路是：AB只讨论了herb的特性，无关；C我一开始觉得就算
others of the closely related group of plants也产生h，也不能说明就是h使它们存活，不过再仔细研读文章后，觉得这
些plants都能在这种soil里存活，又都产生h，也可以支持结论；D我一开始是觉得种了这种plant之后，h就会使土壤中的metal
inert，然后帮助别的plants存活，不过好像也有问题，就是可能是别的原因使其他plants存活；E我是在看了答案之后倒推，觉得h使
metal inert之后，需要的h就越来越少。
于是乎，纠结ing，不知道是不是想太多了，麻烦XDJM给予指导，感激不尽！
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发表于 2009-8-15 19:46:00
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