单项选择题

案例分析题

In recent years a new farming revolution has begun，one that involves the 【B1】______of life at a fundamental level--the gene.The study of genetics has 【B2】______a new industry called biotechnology.As the name suggests，It 【B3】______biology and modern technology through such techniques as genetic engineering.Some of the new biotech companies specialize in agriculture and are working feverishly to 【B4】______seeds that give a high yield，that 【B5】______diseases，drought and frost，and that reduce the need for 【B6】______chemicals.If such goals could be achieved，it would be most 【B7】______.But some have raised concerns about genetically engineered crops.
In nature，genetic diversity is created within certain 【B8】______.A rose can be crossed with a different kind of rose，but a rose will never cross with a potato.Genetic engineering，【B9】______usually involves taking genes from one species and inserting them into another 【B10】______to transfer a desired characteristic.This could mean，for example，selecting a gene which leads to the production of a chemical with anti-freeze 【B11】______from an artic fish，and inserting it into a potato or strawberry to make it frost-resistant.【B12】______，then，biotechnology allows humans to 【B13】______the genetic wails that separate species.
Like the green revolution，【B14】______some call the gene revolution contributes to the problem of genetic uniformity--some say even more so 【B15】______geneticists can employ techniques such as cloning and 【B16】______culture （培养），processes that produce perfectly 【B17】______copies.Concerns about the erosion of biodiversity，therefore，remain.Genetically altered plants，however，raise new 【B18】______，such as the effects that they may have on us and the environment.’We are flying blindly into a new 【B19】______of agricultural biotechnology with high hopes，few constraints，and little idea of the potential 【B20】______’said science writer Jeremy Rifkin.

【B1】（）