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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2023-09-13  45
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] Vaccines for viral diseases are often produced from ______.
选项 A、plant cells
B、human hormones
C、crop plants
D、bacteria
答案 D
解析 这是个细节题，问及抗毒性疾病疫苗从何处提取。从文章第二段第一句话“...the bioengineering of bacteria for the production of...vaccines for viral diseases”可知将细菌生物工程技术应用于生产抗菌素疾病的疫苗。选项A：“植物细胞”，选项 B：“人体激素”，及选项C：“农作物”均不对。
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