Sunflowers growing in pots were placed, with their roots submerged, in the pond contaminated with radioactive elements. The sunflowers kept growing; in the process, they absorbed radioactive elements. Within twelve days, 85 percent of the radioactive elements were removed from the water, which is no less than can be accomplished with the much more expensive conventional filtration techniques. Scientists therefore propose using sunflowers for decontamination wherever there are radioactively contaminated ponds.
Which of the following, if true, points to a limitation on the applicability of the proposed method of decontamination? D
A. Some plants other than sunflowers can also remove radioactive elements from water.
B. The water in many ponds contaminated with radioactive elements is so cold that it would kill sunflowers whose roots were submerged in it.
C. Sunflowers that grow with their roots submerged in water grow less well than sunflowers growing under optimal conditions on dry land.
D. Only species of sunflowers with large leaves can have their roots submerged in water and still keep growing.
E. In ponds in which the circulation of the water is artificially increased, sunflowers absorb radioactive elements far faster than they do in other ponds.
答案给出的是B，我当时选的时候是D。我看了一下以前的帖子，不是很详细。题目问的是LIMITATION，我觉得B和D都有这种限制。但我个人感觉还是D贴近一些。
请不吝赐教！
谢谢，顺便再问一个问题。我觉得我做题的时候很多时候都错在这个范围的问题上？是否说题目中没有给出范围的，选项也不能选限定范围的？
但是我记得以前有看过一些题目答案就是以题目中所述的现象是一种特例来WEAKEN的。
请赐教
谢谢！
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