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  3. Genetically Modified Foods — Feed the World? If you want to spark a heated debate at a dinner party, bring up the topic abou

Genetically Modified Foods — Feed the World? If you want to spark a heated debate at a dinner party, bring up the topic abou

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问题                 Genetically Modified Foods — Feed the World?
    If you want to spark a heated debate at a dinner party, bring up the topic about genetically modified foods. For many people, the concept of genetically altered, high-tech crop production raises all kinds of environmental, health, safety and ethical questions. Particularly in countries with long agrarian (农业的) traditions — and vocal green lobbies — the idea seems against nature.
    In fact, genetically modified foods are already very much a part of our lives. A third of the corn and more than half the soybeans and cotton grown in the U.S. last year were the product of biotechnology, according to the Department of Agriculture. More than 65 million acres of genetically modified crops will be planted in the U.S. this year. The genetic genie is out of the bottle.
    Yet there are clearly some very real issues that need to be resolved. Like any new product entering the food chain, genetically modified foods must be subjected to rigorous testing. In wealthy countries, the debate about biotech is tempered by the fact that we have a rich array of foods to choose from — and a supply that far exceeds our needs. In developing countries desperate to feed fast-growing and underfed populations, the issue is simpler and much more urgent: Do the benefits of biotech outweigh the risks?
    The statistics on population growth and hunger are disturbing. Last year the world’s population reached 6 billion. And by 2050, the UN estimates, it will be probably near 9 billion. Almost all that growth will occur in developing countries. At the same time, the world’s available cultivable land per person is declining. Arable land has declined steadily since 1960 and will decrease by half over the next 50 years, according to the International Service for the Acquisition of Agri-Biotech Applications (ISAAA).
How can biotech help?
    Biotechnologists have developed genetically modified rice that is fortified with beta-carotene (胡萝卜 素) — which the body converts into vitamin A — and additional iron, and they are working on other kinds of nutritionally improved 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. The European corn borer (螟虫) for example, destroys 40 million tons of the world’s corn crops annually, about 7% of the total. Incorporating pest-resistant genes into seeds can help restore the balance. 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 (木薯) crop — a key source of calories — to the mosaic virus. 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 can damage roots and cause many staple-crop failures. A gene that helps neutralize aluminum toxicity (毒性) 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 before 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. Today more than 1 billion people around the globe live on less than 1 dollar a day. 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.
    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 needs of poor countries.
    More and more biotech research is being carried out in developing countries. But 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. The ISAAA, for example, is successfully partnering with the U.S. Agency for International Development, local researches and private biotech companies to find and deliver biotech solutions for farmers in developing countries.
Will "Franken-foods" feed the world?
    Biotech is not a panacea (治百病的药), 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.
    The world seems increasingly to have been divided into those who favor genetically modified (GM) foods and those who fear them. Advocates assert that growing genetically altered crops can be kinder to the environment and that eating foods from those plants is perfectly safe. And, they say, genetic engineering — which can induce plants to grow in poor soils or to produce more nutritious foods — will soon become an essential tool for helping to feed the world’s burgeoning (迅速发展的) population. Skeptics contend that genetically modified crops could pose unique risks to the environment and to health — risks too troubling to accept placidly. Taking that view, many European countries are restricting the planting and importation of genetically modified agricultural products. Much of the debate hinges on perceptions of safety. But what exactly does recent scientific research say about the hazards?
    Two years ago in Edinburgh, Scotland, eco-vandals stormed a field, crushing canola plants. Last year in Maine, midnight raiders hacked down more than 3,000 experimental poplar trees. And in San Diego, protesters smashed sorghum and sprayed paint over greenhouse walls.
    This far-flung outrage took aim at genetically modified crops. But the protests backfired: all the destroyed plants were conventionally bred. In each case, activists mistook ordinary plants for genetically modified varieties.
    It’s easy to understand why. In a way, genetically modified crops — now on some 109 million acres of farmland worldwide — are invisible. You can’t see, taste or touch a gene inserted into a plant or sense its effects on the environment. You can’t tell, just by looking, whether pollen containing a foreign gene can poison butterflies or fertilize plants miles away. That invisibility is precisely what worries people. How, exactly, will genetically modified crops affect the environment — and when will we notice?
    Advocates of genetically modified or transgenic crops say the plants will benefit the environment by requiring fewer toxic pesticides than conventional crops. But critics fear the potential risks and wonder how big the benefits really are. "We have so many questions about these plants," remarks Guenther Stotzky, a soil microbiologist at New York University. "There’s a lot we don’t know and need to find out."
    As genetically modified crops multiply in the landscape, unprecedented numbers of researchers have started fanning into the fields to get the missing information. Some of their recent findings are reassuring; others suggest a need for vigilance.
Raiders missed the genetically modified varieties because of the______of such plants.
选项
答案invisibility
解析 第四段末句说袭击者们搞错了袭击对象，他们袭击的都不是转基因作物。第五段首句就说其中原因很容易理解(It’s easy to understand why．)。接着解释原因：转基因作物是无形的(invisible).根据题干的要求，在空格处应填入invisible的名词形式invisibility.
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