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 答案选C,个人感觉C是无关选项。 In Patton City, days are categorized as having heavy rainfall (more than two inches), moderate rainfall (more than one inch, but no more than two inches), light rainfall (at least a trace, but no more than one inch), or no rainfall. In 1990, there were fewer days with light rainfall than in 1910 and fewer with moderate rainfall, yet total rainfall for the year was 20 percent higher in 1990 than in 1910. If the statements above are true, then it is also possible that in Patton City A. the number of days with heavy rainfall was lower in 1990 than in 1910 B. the number of days with some rainfall, but no more than two inches, was the same in 1990 as in 1910 C. the number of days with some rainfall, but no more than two inches, was higher in 1990 than in 1910 D. the total number of inches of rain that fell on days with moderate rainfall in 1990 was more than twice what it had been in 1910 E. the average amount of rainfall per month was lower in 1990 than in 1910 答案选A,但是我觉得A肯定不对啊,moderate和light的天数都少了,只有heavy的天数多才能保证总降雨量变大了阿。。。 请指教,谢谢! |