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  3. Across the United States, scientists are mounting what may become the most i

Across the United States, scientists are mounting what may become the most i

游客2024-06-09  39
问题     Across the United States, scientists are mounting what may become the most innovative agricultural research drive since the 1920’s, when hybrid corn was developed. Surprisingly, the new genetic revolution is not taking place in America’s fields. Instead, it is occurring in biology laboratories, for it involves the deliberate manipulation in test tubes of the genes of crop plants. This genetic engineering may prove the biggest boon to agriculture since plant breeding began.
    The new concepts grew out of the bioengineering of bacteria for the production of such things as human hormones and vaccines for viral diseases. Plant cells, however, are far more complex than bacteria, and it will probably take many years for today’s encouraging laboratory results to have a major impact on the farm. In fact the payoff may not come until the next century.
    But although bio-technologists are still in the earliest phases of this new field of science, they are already actively exploring ways to redesign plants so they will use sunlight mere efficiently, resist viruses and other pests, grow in hot or dry areas, in saline soils or in the presence of pesticides, and perhaps even make their own fertilizer out of nitrogen in the air. In addition, scientists have had early success in making wholly new plants that are unavailable by conventional plant breeding-a potato-tomato combination, for example.
    The new technology holds the promise of virtually limitless horizons in food production. Only imagination sets the limits: frost-resistant wheat, tropical potatoes, saltwater rice, a plant producing a combination of a pea and a carrot-all may be with us one day. [br] From the passage we understand that conventional plant breeding produced ______.
选项 A、a potato-tomato hybrid
B、new plant technology
C、self fertilizing
D、less dramatic results than the new technology
答案 D
解析 本题问及传统作物育种的后果如何。文章后两段讲的是利用基因工程能培植出传统农业无法达到的引人注目的结果并且前景无限。反过来说，即传统农业育种不如新育种技术结果吸引人，故选D。选项A，C都是新技术的结果，选项B的错误在于：新农业技术与传统农业技术不是产生与被产生的关系。
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