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
不太赞成c啊。。原文结论是"the herb's..."答案应该只refer to this kind of herb rather than its closely related group of plants吧。个人认为C是干扰相,实则为无关项,原文要求加强的结论是“h这种物质和这种herb能在metal-rich soils里存活的关系”,对象是这种特指的herb:“the herb’s high histidine production is whatallows it to grow in metal-rich soils”。 再看D,原文说“ itproduces large amounts of histidine, an amino acid that, in test-tubesolutions, renders these metals chemically inert.” D选项很好地填补了gap,紧贴结论:“cultivation of the herb in soil with highconcentrations of the metals will, over an extended period, make the soilsuitable for plants to which the metals are toxic”
No. The conclusion of the passage is: the herb’s high histidine production is what allows it to grow in metal-rich soils.
D) does not strengthen this conclusion, since D) only confirms that the herb can survive but D) is moot as to the REASON why it does so.
I chose D, and in fact, some plants really do that with histidine.
E) is a wrong answer.
E) the concentration of histidine in the growing herb declines as the plant approaches maturity. If so, then the herb has less and less histidine before REACHING adulthood. And if histidine is required for the herb to survive in the metal-rich soil, the herb would DIE before reaching maturity. This is CONTRARY to the premise: the herb THRIVES in that type of soil.
I chose D, and in fact, some plants really do that with histidine.
E) is a wrong answer.
E) the concentration of histidine in the growing herb declines as the plant approaches maturity. If so, then the herb has less and less histidine before REACHING adulthood. And if histidine is required for the herb to survive in the metal-rich soil, the herb would DIE before reaching maturity. This is CONTRARY to the premise: the herb THRIVES in that type of soil.
E) the concentration of histidine in the growing herb declines as the plant approaches maturity. If so, then the herb has less and less histidine before REACHING adulthood. And if histidine is required for the herb to survive in the metal-rich soil, the herb would DIE before reaching maturity. This is CONTRARY to the premise: the herb THRIVES in that type of soil.