单选题Passage One 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.
单选题
According to the author, biotech companies are______. A. mostly specialized in agriculture B. those producing seeds of better properties C. mainly concerned about the genetically engineered crops D. likely to have big returns in their business
【正确答案】
D
【答案解析】[解析] 从第一段第一句可以看出，生物技术公司在其业务上可能有利可图。
单选题
Now biotech products are made______. A. within the limits of natural genetics B. by violating laws of natural genetics C. without the interference of humans D. safer than those without the use of biotechnology
【正确答案】
A
【答案解析】[解析] 从第二段第四句可以看出，新的生物技术产品都有其局限性。
单选题
In nature, genetic diversity is created______. A. by mixing different species B. within the species itself C. through natural selection D. through selection or contest
【正确答案】
A
【答案解析】[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。
单选题
Biotechnology has made it possible______. A. for us to solve the food shortage problem in the word B. for plants to be produced with genes of humans C. for humans to assume the cold-resistant property D. to grow crops with the taste of farm animals
【正确答案】
D
【答案解析】[解析] 从第二段倒数第二句可以看出，生物技术使得一些物种与动物基因互相转化成为可能。
单选题
According to the author with of biotechnology______. A. the species of creatures will be reduced B. our living environment will be better than it is now C. humans will pay for its side effect D. we will suffer from fewer and fewer diseases
【正确答案】
C
【答案解析】[解析] 从最后一段倒数第二句可以看出，随着生物技术发展，人类会为其负面效应付出代价。
单选题
The author's attitude towards genetic engineering can best be described as______. A. optimistic B. pessimistic C. concerned D. suspicious