作者: sdcar2010 时间: 2011-1-24 00:38
Certain genetically modified strains of maize produce a powerful natural insecticide. The insecticide occurs throughout the plant, including its pollen. Maize pollen is dispersed by the wind and frequently blows onto milkweed plants that grow near maize fields. Caterpillars of monarch butterflies feed exclusively on milkweed leaves. When these caterpillars are fed milkweed leaves dusted with pollen from modified maize plants, they die. Therefore, by using genetically modified maize, farmers put monarch butterflies at risk. Which of the following would it be most useful to determine in order to evaluate the argument? A. Whether the natural insecticide is as effective against maize-eating insects as commercial insecticides typically used on maize are B. Whether the pollen of genetically modified maize contains as much insecticide as other parts of these plants C. Whether monarch butterfly caterpillars are actively feeding during the part of the growing season when maize is releasing pollen D. Whether insects that feed on genetically modified maize plants are likely to be killed by insecticide from the plant’s pollen E. Whether any maize-eating insects compete with monarch caterpillars for the leaves of milkweed plants growing near maize fields
Why does E matter with regard to the argument? Since the pollen is toxic to insects, all insects eating the pollen, either directly from the maize or the leaves of milkweek will die.作者: echine 时间: 2011-1-24 09:22
明白了，insecticide,谢谢！ PS：题目发的太不清晰，对不住大家！作者: gwang5 时间: 2011-1-24 21:42
SDCAR真是好人啊！这么花眼的题目都有爱心去回复！作者: gjyrxqgzj 时间: 2011-6-12 16:49
对E还是有些疑问 如果maize-eating insects把milkweed leaves都吃掉了，monarch caterpillars吃不到milkweed leaves，不受insecticide的影响，不也weaken argument 吗？