Biotechnologists have developed genetically modified rice that is fortified with beta carotene which the body converts into vita

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问题     Biotechnologists have developed genetically modified rice that is fortified with beta carotene which the body converts into vitamin A and additional iron, and they are working on three kinds of nutritionally in proved crops. Biotech can also improve farming productivity in places where food shortages are caused by crop damage attributable to pests, drought, poor soil and crop viruses, bacteria or fungi. Damage caused by pests is incredible. In trials of pest-resistant cotton in Africa yields have increased significantly. So far, fears that genetically modified, pest-resistant crops might kill good insects as well as bad appear unfounded. Viruses often cause massive failure in staple crops in developing countries. Two years ago Africa lost more than half its cassava crop—a key source of calories—to the mosaic virus. Genetically modified, virus resistant crops can re duce that damage, as can drought-tolerant seeds in regions where water shortage limits the amount of land under cultivation. Biotech can also help solve the problem of soil that contains excess aluminum, which can damage roots and cause many staple-crop failures. A gene that helps neutralize aluminum toxicity in rice has been identified. 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 simply 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 the rich countries carry out much of the leading-edge research on genetically modified crops. 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 in order to help them rapidly recoup the high costs of product development. But some of these companies are responding to the needs of poor countries. To increase the impact of genetic research on the food production of those countries, there is a need for better collaboration between government agencies—both local and in developed countries—and private biotech firms.
    Biotech is not a panacea, but it does promise to transform agriculture in many developing countries. If that promise is not fulfilled, the real losers will be their people, who could suffer for years to come.

选项 A、The genetically modified, pest-resistant crops might kill good insects as well as bad ones.
B、It can help solve the problem of soil that contains little aluminum.
C、It could overcome the challenge of distributing food in developing countries.
D、It can help prevent the loss of those crops before they are harvested.

答案D

解析 分析推理题。文章第一段介绍子生物技术对农业的正面影响。从第二句开始,介绍的都是生物技术如何提高作物产量,提高作物抵抗病虫害,改善土壤中过量铝元素等对作物带来的不良影响等,综合起来就是使作物收割前减少损失。
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