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?
C. Whether monarch butterfly caterpillars are actively feeding during the part of the growing season when maize is releasing pollen
E. Whether any maize-eating insects compete with monarch caterpillars for the leaves of milkweed plants growing near maize fields
E选项：其他insects与caterpillars争着吃maize。不就是evaluate “by using genetically modified maize, farmers put monarch butterflies at risk.”
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发表于 2012-1-14 21:27:42
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