[提问] GWD－TN－10～～求各位同学进来看看！

劳小狮

原文：

          Moreselective than most chemical pesticides in that they ordinarily destroy onlyunwanted species, biocontrol agents (such as insects, fungi, and viruses) eat,infect, or parasitize targeted plant or animal pests. However, biocontrolagents can negatively affect nontarget species by, for example, competing withthem for resources: a biocontrol agent might reduce the benefits conferred by adesirable animal species by consuming a plant on which the animal prefers tolay its eggs. Anotherexample of indirect negative consequences occurred in England when avirus introduced to control rabbits reduced the amount of open ground (becauselarge rabbit populations reduce the ground cover), in turn reducing undergroundant nests and triggering the extinction of a blue butterfly that had dependedon the nests to shelter its offspring. The paucity of knownextinctions or disruptions resulting from indirect interactions may reflect notthe infrequency of such mishaps but rather the failure to look for or to detectthem: most organisms likely to be adversely affected by indirect interactionsare of little or no known commercial value and the events linking a biocontrol agentwith an adverse effect are often unclear. Moreover, determining the potentialrisks of biocontrol agents before they are used is difficult, especially when a nonnative agent is introduced,because, unlike a chemical pesticide, a biocontrol agent may adapt inunpredictable ways, so that it can feed on or otherwise harm new hosts.

GWD-24-6

The example presented by the author in lines 14-23 mostclearly serves to illustrate

A.     a situation inwhich a species is less vulnerable to biocontrol agents than it would have beento chemical pesticides.

B.      a way in whichthe introduction of a biocontrol agent can affect a nontarget species.

C.     a nonnativeagent’s adapting in an unpredictable way that results in damage to a new host.

D.     The contentionthat biocontrol agents can harm nontarget species by competing with them forresources

E.      the way in whichindirect consequences from the use of biocontrol agents are most likely tooccurs.

正确答案是B，我选了E
真心分不出这两个选项有什么不一样阿。。。求助求助！！！