标题: PREP2-4-Q15 [打印本页]
作者: monsterld 时间: 2011-8-26 06:28 标题: PREP2-4-Q15
Solar ponds are bodies of water in which circulation is incomplete and there is a very high salt concentration that increases with depth.This vertical change in salinity serves to trap heat because concentrated brine in the lowest water level acts as a collector and storage area for solar heat, while the less saline, lighter water at the upper levels provides insulation.Heat is thus retained in the depths.
An artificial pond of this type has been constructed on the western shore of the Dead Sea in Israel in order to test its suitability as a source of low-One proposed method of controlling the algae was the application of an algicide.However, the Dead Sea is a closed body of water without any outlet and as such is very easily contaminated.Extensive use of chemicals in numerous future full-scale solar ponds would lead to such contamination of the Dead Sea, which now enjoys a lucrative tourist trade.
A recent experiment has supplied a more promising method for controlling the algae.To repress the algae cells' capacity for accommodating themselves to environmental changes, the water in the solar pond was first made more saline through evaporation and then diluted by a rapid inflow of fresh water.This shock reduced the cells' ability to regulate the movement of water through their membranes.They rapidly absorbed water, resulting in distortions of shape, increase in volume, and impairment to motility.Their buoyancy adversely affected, the cells sank to the bottom of the pond, where they encountered the hot waters of the storage layer and were destroyed.This method allows for effective control of nuisance algae while leaving solar ponds as one of the cleanest technologies providing energy for human use.
Which of the following, if true, would seriously undermine the validity of the conclusions drawn from the experiment described in the last paragraph of the passage?
(A) The algae cells that sank to the bottom of the pond were destroyed only after a time lag of twenty-four hours.
(B) The lateral motility of the algae cells that sank to the bottom of the pond was not impaired.
(C) The water with which the artificial solar pond was diluted contained microorganisms that kill algae.
(D) The algae cells that sank to the bottom of the pond were actually killed by the rapid change in pressure.
(E) The higher salinity brought about through evaporation increased the transparency of the upper levels of water in the pond.
亲爱的各位NN们，此题的答案是C，是在搞不懂为什么和C有关，想来想去还是觉得A对嘛~
期待大家为我解释解释，谢谢啦~
ps：哪里有PREP破解版阅读的所有解释啊，这样就不用每次上来求解释咯~
作者: luke-216 时间: 2011-8-26 21:46
刚刚做到这题也错了~我觉得选C可能是因为C提供了其他原因（微生物）导致algae死掉而不是hot water。。。
但至于怎么undermine了conclusion。。难道微生物还会影响盐水池储存热量？
作者: cherryserena 时间: 2011-8-27 20:48
楼主你看，我是这么理解的：
既然题目问“undermine the validity of the conclusions drawn from the experiment” 那么首先应该先找到这个实验的结论是什么。这个实验用的是这么一个逻辑。
含盐量高的水上有适合了这种环境的细胞（水藻的细胞）--- 加大量的含盐量低的水---- 破坏了原有的平衡-----细胞大量吸水----细胞变形，不蠕动等等----原有的浮力系统被破坏---下沉----被烫死（==！）
好了，这样的原理被推出来。很环保，不加有毒物质。所以，理所应当的结论就是 “这个方法可以消灭水藻”。
看选项~ A，貌似还可以成立，24小时候也是消灭了嘛~
C，典型的逻辑题目。就不解释啦~
作者: monsterld 时间: 2011-8-28 19:41
谢谢，我想请问哪里可以找到所有prep的阅读解释呢？
作者: cherryserena 时间: 2011-8-29 06:25
这个我也不清楚~应该还没有吧~希望有达人可以出一个.....
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