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题库 / Prep2007E2-CR-22
Herbicides allow cereal crops to be grown very efficiently, with virtually no competition from weeds. In Britain, partridge populations have been steadily decreasing since herbicide use became widespread. Some environmentalists claim that these birds, which live in and around cereal crop fields, are being poisoned by the herbicides. However, tests show no more than trace quantities of herbicides in partridges on herbicide-treated land. Therefore, something other than herbicide use must be responsible for the population decrease.
Which of the following, if true about Britain, most seriously weakens the argument?
The elimination of certain weeds from cereal crop fields has reduced the population of the small insects that live on those weeds and that form a major part of partridge chicks' diet.
Since partridges are valued as game birds, records of their population are more carefully kept than those for many other birds.
Some of the weeds that are eliminated from cereal crop fields by herbicides are much smaller than the crop plants themselves and would have no negative effect on crop yield if they were allowed to grow.
Birds other than partridges that live in or around cereal crop fields have also been suffering population declines.
The toxins contained in herbicides typically used on cereal crops can be readily identified in the tissues of animals that have ingested them.
选项A不是滑坡理论吗？除草剂→草减少→吃这种草的昆虫减少→吃这个昆虫的鹧鸪减少，不能推出除草剂能导致鹧鸪数量减少啊
还想问一下选项E为什么不对呢？谢谢老师~
E的意思是杀虫挤毒素能够readily(adv.容易地；乐意地；无困难地)被鉴定出来，只要动物吃了差冲剂，言外之意就是p鸟
E的意思是杀虫挤毒素能够readily(adv.容易地；乐意地；无困难地)被鉴定出来，只要动物吃了差冲剂，言外之意就是p鸟
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