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.”
