28. GWD28-Q28:
Which of the following most logically completes the argument?[h1]
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. [h2] 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. [h3] 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 ______.[h4]
histidine is found in all parts of the plant—roots, stem, leaves, and flowers
the herb’s high level of histidine production is found to be associated with an unusually low level of production of other amino acids[h5]
others of the closely related group of plants are also found to produce histidine in large quantities[h6]
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[h7]
the concentration of histidine in the growing herb declines as the plant approaches maturity
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[h1]
[h2]这句介绍了这个草的特性（一群草的共性）：就是可以活在有毒金属泛滥的土壤里。
[h3]这句就说了这个草有histidine这玩艺，一帮科学家发现histidine的试管溶液有make metals chemically inert的功能。注意，只是农科院的老板叫学生在实验室拿试管晃了晃histidine溶液，没真刀真枪的搞那根草。
[h4]于是乎，老板就说是那根草的histidine让它能在地里长，不过要学生多拿一点数据来攒paper灌水。整个的逻辑缺什么呢？就是histidine Vs. metal的实验不是草里的h和地里m，一句话，没下地干活不给毕业。
[h5]
[h6]
如果题干拿掉第2句就一定是错的，何况第2句本身还要加强呢。本来就是亲戚，都长一样的东西很正常嘛，可不见得一定是这个东西有什么用哦。
等於是加強了樣本的代表性。
[h7]Ok.
D回答了这个问题，那些金属是有毒的，种了草之后就inert了，很符合试验室结果。应该是histidine的功能。
注意这是一道支持题，不是evaluate题，所以答案的是与非不会对原结论产生天壤之别。因为是支持题，所以只要答案与原结论方向一致并且起到加强作用即可。
d? | 
