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  3. With rapid growth of world population, mainly in developing countries, the available cultivable land per person has declined ste

With rapid growth of world population, mainly in developing countries, the available cultivable land per person has declined ste

admin2010-12-04  57
问题       With rapid growth of world population, mainly in developing countries, the available cultivable land per person has declined steadily since 1960 and will decease by half over the next 50 years. Besides, about 400 million women of childbearing age are iron deficient, leaving their babies exposed to various birth defects. As many as 100 million children suffer from vitamin A deficiency. Tens of millions of people suffer from other major ailments and nutritional deficiencies caused by lack of food.
      How can biotech help? Biotechnologists have developed genetically modified rice fortified with beta carotene (β-胡萝卜素) and additional iron, and they are working on other kinds of nutritionally improved crops. Biotech can also improve farming productivity in places where crop failures are caused by pests, drought, poor soil and crop viruses, bacteria or fungi. Genetically modified, virus-resistant crops can reduce that damage, as can drought-tolerant seeds in regions where water shortages limit the amount of land under cultivation. Biotech can also help solve the problem of soil that contains excess aluminum, which damages roots and causes staple crop failures.
      Many scientists believe biotech could raise overall crop productivity in developing countries as much as 25% and help prevent the loss of those crops after they are harvested. Yet for all that promise, biotech is far from being the whole answer. In developing countries, lost crops are only one cause of hunger. Poverty plays the largest role. Making genetically modified crops available will not reduce hunger if farmers cannot afford to grow them or if the local population cannot afford to buy the food those farmers produce.
      Nor can biotech overcome the challenge of distributing food in developing countries. Taken as a whole, the world produces enough food to feed everyone--but much of it is in the wrong place. Especially in countries with undeveloped transport infrastructures, geography restricts food availability as dramatically as genetics promises to improve it.
      Biotech has its own "distribution" problems. Private-sector biotech companies in rich countries carry out much of the leading-edge research. Their products are often too costly for poor farmers in the developing world, and many of those products won’t even reach the regions where they are most needed. Biotech firms have a strong financial incentive to target rich markets first to help them rapidly recoup the high costs of product development. But some companies are responding to the needs.  
Biotech can’t solve the problem of distributing food in developing nations because ______.
选项 A、enough food can be produced to feed world population
B、the transport infrastructure in some countries are backward
C、biotech itself can not be distributed to these countries
D、farmers in those nations can not afford to buy the technology
答案B
解析 但大部分粮食却不是在需要的地方，尤其在运输基础设施落后的国家，地理条件限制了粮食的运输。因此答案为B)。
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