1，碰到一题GWD原题。说一个海滩有大量浮游生物（或者微生物什么的）聚集，有人调查发现没有浮游生物聚集的区域缺铁。于是科学家做了实验，把铁注入某个海域，结果发现还是没有浮游生物聚集，问解释。答案是注入的铁在几天内被洋流冲走了。
我手头现没有GWD CR,急!
谢!
Plankton generally thrive in areas of the ocean with sufficient concentrations of certain nitrogen compounds near the surface, where plankton live. Nevertheless, some areas, though rich in these nitrogen compounds, have few plankton. These areas have particularly low concentrations of iron, and oceanographers hypothesize that this shortage of iron prevents plankton from thriving. However, an experimental release of iron compounds into one such area failed to produce a thriving plankton population, even though local iron concentrations increased immediately.
Which of the following, if true, argues most strongly against concluding, on the basis of the information above, that the oceanographers’ hypothesis is false?
A. Not all of the nitrogen compounds that are sometimes found in relatively high concentrations in the oceans are nutrients for plankton.
B. Certain areas of the ocean support an abundance of plankton despite having particularly low concentrations of iron.
C. The release of the iron compounds did not increase the supply of nitrogen compounds in the area.
D. A few days after the iron compounds were released, ocean currents displaced the iron-rich water from the surface.
E. The iron compounds released into the area occur naturally in areas of the ocean where plankton thrive.
xiexie!
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