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  3. The study of genetics has given rise to a profitable new industry called biotechnology. As the name suggests, it blends biology

The study of genetics has given rise to a profitable new industry called biotechnology. As the name suggests, it blends biology

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问题     The study of genetics has given rise to a profitable new industry called biotechnology. As the name suggests, it blends biology and modem technology through such techniques as genetic engineering. Some of the new biotech as they are called, specialize in agriculture and are working enthusiastically to patent seeds that give a high yield, that resist disease, drought, and frost, and that reduce the need for hazardous chemicals. If such goals could be achieved, it would be most beneficial. But some have raised concerns about genetically engineered crops.
    "In nature, genetic diversity is created within certain limits," says the book Genetic Engineering, Food, and Our Environment. "A rose can be crossed with a different kind of rose, but a rose will never cross with a potato. Genetic engineering, on the other hand, usually involves taking genes from one species and inserting them into another in an attempt to transfer a desired property or character. This could mean, for example, selecting a gene which leads to the production of a chemical with antifreeze properties from an arctic fish, and joining it into a potato or strawberry to make it frost-resistant. It is now possible for plants to be engineered with genes taken from bacteria, viruses, insects, animals or even humans." In essence, then, biotechnology allows humans to break the genetic walls that separate species.
    Like the green revolution, what some call the gene revolution contributes to the problem of genetic uniformity—some say even more so because geneticists can employ techniques such as cloning and tissue culture, processes that produce perfectly identical copies, or clones. Concerns about the erosion of biodiversity, therefore, remain. Genetically altered plants, however, raise new issues, such as the effects that they may have on us and the environment. "We are flying blindly into a new era of agricultural biotechnology with high hopes, few constraints, and little idea of the potential outcomes," said science writer Jeremy Rifkin.
In nature, genetic diversity is created______.
选项 A、by mixing different species
B、within the species itself
C、through natural selection
D、through selection or contest
答案A
解析 从第二段最后一句可以看出，基因多样性是不同基因物种的混合体。
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