标题: 求教一道GWD CR题 ～～ [打印本页] 作者: zxtwillima 时间: 2012-7-19 15:35 标题: 求教一道GWD CR题 ～～ 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.作者: gavenxsn 时间: 2012-7-19 17:10
文章反复在谈到iron对plankton的影响~however后面说的是放了iron对plankton没影响，那会不会有一种因素影响了iron呢？ A.再谈nitro，无关 B.如果真是这样还要iron干啥，去掉 C.nitro都那么多了还增加，明显无关 D.好像读起来是影响因素，因为海水把iron冲走了~不就没影响了吗 E.都有iron了它就应该thrive啊，去掉