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Certain genetically modified strains of maize produce a natural insecticide that protects against maize-eating insects. The insecticide occurs throughout the plant, including its pollen. Maize pollen is dispersed by the wind and often blows onto milkweed plants that grow near maize fields. Caterpillars of monarch butterflies feed exclusively on milkweed leaves. When, in experiments, these caterpillars were fed milkweed leaves dusted with pollen from modified maize plants, they died. Therefore, use of the modified maize inadvertently imperils monarch butterflies.
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.
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发表于 2008-5-10 20:24:00
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