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  3. In 1798 the political economist Malthus predicted that in time mankind would

In 1798 the political economist Malthus predicted that in time mankind would

游客2025-04-20  22
问题     In 1798 the political economist Malthus predicted that in time mankind would face starvation, having outgrown the available food supplies. Today, a century and a half later, there are still experts who forecast the same global disaster unless urgent measures are taken to prevent it.
    By the end of the present century there may well be over five thousand million people living on this globe, ail increase of over fifty per cent of today’s figure. In order to keep pace with this increase in mankind the farmers of the world would have to step up their production of food by at least two per cent every year. Such a rate of increase has never been maintained in any country by conventional methods of agriculture, despite modern mechanization and the widespread use of fertilizers. There are no large worthwhile reserves of potential farmland, remaining, and good fertile land is continually being diverted to industrial use. Moreover, erosion of the soil takes a constant toll.
    Intensive research, carried out over many years in all manner of climatic conditions, has produced a revolutionary method of growing crops without using any soil at all. Hydroponics, as this technique is called, may well be the answer to all our food worries. Already it has accomplished wonders in producing huge crops. Hydroponics was once a complicated and expensive business; now it is well out of the experimental stage. Labor costs are far lower than when normal methods of agriculture are employed. In fact, it is a completely automatic system. There is no hard manual work, no digging or plowing, and no weeding to speak of. Yields can be far higher than they are in soil. [br] According to the author, 2 percent annual increase in the production of food can not be achieved. Which of the following is not the explanation he gave for the problem?
选项 A、There are not enough potential farmland reserves left.
B、Land is being lost through erosion and industrialization.
C、Conventional methods of agriculture are still prevailing all over the world.
D、Modern mechanization and the use of fertilizers are not well popularized in the world.
答案 D
解析 根据第二段可知，食物生产落后于人口需求至少2％，传统耕种方式、备用耕地不足以及土壤流失都是因素，由此可知答案为D。
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