GRE Reading Comprehension: JiJing 352-GRE阅读机经352篇 - O5TT7A7FYA554G7PJ

The author introduces statistics about North America's non-indigenous plant species primarily in order to A. undermine a proposed explanation for the absence of any evidence for the occurrence of a particular phenomenon B. contrast the effect of introduced plant species in North America with the effect that introduced animal species have had C. suggest that North America's indigenous plants are a domain in which there has been ample scope for a particular effect to have occurred D. emphasize how much the ecology of North America has been affected over the past 400 years by the introduction of non-indigenous species E. substantiate a claim about the overall effect that the introduction of non-indigenous species tends to have on indigenous populations