【单选题】{{B}}Passage Two{{/B}}
"The result may be very hardy, hard-to-kill weeds," saidAllison Snow, a plant ecologist at Ohio State University inColumbus who conducted the experiments over the past six years along with two colleagues. They presented their results last week at the annual meeting of theEcological Society ofAmerica in Madison, Wisconsin.
The findings suggest that genetic engineering done with the aim of improving crops--growing the new genetic traits such as resistance to herbicides or pests-- could ultimately have unintended and harmful consequences for the crops if weeds acquire the same trait and use it to out-compete the crops. "Gene movement from crops to their wild relatives is an ongoing process that can be ultimately harmful to crops," said Snow.
The results of the experiments challenge a common belief that hybrids gradually die out over several generations, Snow explaineD、"There has been an assumption that crop genes wouldn’t persist in crop-weed hybrids" because hybrids are thought to be less successful at reproducing, she saiD、However, Snow’s research contradicted this assumption: Hybrid wild radishes survived in all six generations that were grown since the study began.
Although the genetic traits the scientists monitored were natural and not genetically engineered, the findings nonetheless suggest that artificial improvements introduced into crops through genetic engineering could spread to weeds and become permanent traits of the weed population.
So strengthened, the weeds may pose a serious risk to the long-term health of agricultural crops. The danger exists in a number of crop plants--including rice, sunflower, sorghum, squash, and carrots--that are closely related to weeds with which they compete. Snow is concerned that the transfer of genes from crops to related weeds could rapidly render many herbicides (chemicals which kill weeds) ineffectual. That situation, she said, would be much like bacterial diseases acquiring resistance to antibiotics.
Because plant hybrids arise in a single generation, however, it could happen much more quickly; "Modern agriculture is heavily dependent on herbicides," she said, "so people will notice when those don’t work anymore."
B．the collapse of the agricultural industry
C．the development of pest and herbicide-resistant weeds
D．the difficulty to determine the given nature of current research
网考网参考答案：C
网考网解析：
这是一道推论题。文章最后两段指出：斯诺担心的是，基因从农作物转移到这些有关的杂草上可能使除草剂迅速失效；现代农业非常依赖于除草剂，所以人们会注意这些除草剂何时会失效。由此可知，基因从农作物到杂草的转变可能产生的主要影响就是能够抵抗除草剂的杂草和害虫的肆意发展。C与文章的意思相符。与A有关的信息是第三段的第一句话，文中是说“……最终可能会对农作物产生无意识的、有害的结果”，这明显与题目的要求不符；文中没有提到B和D。 document.getElementById("warp").style.display="none"; document.getElementById("content").style.display="block"; 查看试题解析出处>>
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