标题: 请教 OG 12 中 CR 32 [打印本页] 作者: robbinpeng 时间: 2010-7-21 23:42 标题: 请教 OG 12 中 CR 32 The Eurasian ruffe, a fi sh species inadvertently introduced into North America’s Great Lakes in recent years, feeds on the eggs of lake whitefi sh, a native species, thus threatening the lakes’ natural ecosystem. To help track the ruffe’s spread, government agencies have produced wallet-sized cards about the ruffe. The cards contain pictures of the ruffe and explain the danger they pose; the cards also request anglers to report any ruffe they catch. Which of the following, if true, would provide most support for the prediction that the agencies’ action will have its intended effect? (A) The ruffe has spiny fi ns that make it unattractive as prey. (B) Ruffe generally feed at night, but most recreational fi shing on the Great Lakes is done during daytime hours. (C) Most people who fi sh recreationally on the Great Lakes are interested in the preservation of the lake whitefi sh because it is a highly prized game fi sh. (D) The ruffe is one of several nonnative species in the Great Lakes whose existence threatens the survival of lake whitefi sh populations there. (E) The bait that most people use when fi shing for whitefi sh on the Great Lakes is not attractive to ruffe.