填空题

The study of genetics has given rise to a profitable new industry called biotechnology. As the name __31__ , it combines biology and modern technology through such __32__ as genetic engineering. Some of the new biotech companies, as they are called, __33__ in agriculture and are working enthusiastically to patent (取得专利) seeds that give a high yield (产量), that __34__ disease, drought and frost, and that reduce the need for dangerous chemicals. __35__ such goals could be achieved, it would be most beneficial. But some have raised __36__ about genetically engineered crops. "In nature, genetic diversity (多样性) is created within certain limits," says the book Genetic Engineering, Food and Our Environment. "A rose can be crossed(杂交) with a different kind of rose, but a lose will __37__ 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 __38__ a desired property or character. This could mean, __39__ , 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 __40__ from bacteria, viruses, insects, animals or even humans. __41__ , then, biotechnology allows humans to break the genetic walls that __42__ species. Like the green revolution, (43)what some call the gene revolution (44)contributes to the problem of genetic uniformity (千篇一律) –some say even more so (45)because geneticists can employ techniques such (46)as cloning and organ culture, processes that produce perfectly (47)identical copies, or clones. Concerns about the biodiversity, therefore, remain. Genetically altered plants, however, raise new(48) issues, such as the effects that they may have on us and the environment. ―We are flying blindly into a new (49) of agricultural biotechnology with high hopes, few constraints, and little idea of the potensial (50) , said science writer Jeremy Rifkin.