2. 外语
  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

admin2013-02-05  53
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 (疾病) and nutritional deficiencies caused by lack of food.
    How can biotech help? Biotechnologists have developed genetically modified rice that is 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 or bacteria. 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 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 (收回) the high costs of product development. But some companies are responding to the needs.
Biotechnologists can help reduce illnesses related to nutritional deficiencies by______.
选项 A、developing genetically modified or nutritionally improved crops
B、incorporating pest-resistant or virus-resistant genes into seeds of crops
C、improving the ability of seeds to resist water shortages in certain regions
D、solving the problem of soil that contains excess aluminum
答案A
解析 事实细节题。第二段主要说明生物科技尤其是转基因技术在农业中的应用，首先承接第一段中的种种问题，提出生物科技专家们培育转基因水稻和其他增强营养成分的作物可以解决营养不良的问题。故A)为本题答案。
转载请注明原文地址:https://kaotiyun.com/show/qjI7777K
0

大学英语六级

相关试题推荐
随机试题
最新回复(0)