题目内容：
Directions : There are 20 blanks in the following passage. For each blank there are four choices marked A, B, C and D on the right side of the paper. You should choose the ONE that best fits into the passage. Then mark the corresponding letter on Answer Sheet 2 with a single line through the centre.In recent years a new farming revolution has begun, one that involves the 1 of life at a fundamental level -- the gene. The study of genetics has 2 rise to a new industry calledBiotechnology. As the name suggests, it 3 biology and modern technology through such techniques as genetic engineering. Some of the new biotech companies specialize in agriculture and are working feverishly to 4 seeds that give a high yield, that 5 diseases, drought and frost, and that reduce the need for 6 chemicals. If such goals could be achieved, it would be most 7 . But some have raised concerns about genetically engineered crops.
In nature, genetic diversity is created within certain 8 ．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 9 taking genes from one species and inserting them into another in a(n) 10 to transfer a desired characteristic．This could mean，for example，selecting a gene which leads to the production of a chemical with antifreeze 11 from an arctic fish，and inserting it into a potato or strawberry to make it frost—resistant．In 12 ，then，biotechnology allows humans to 13 the genetic walls that separate species．
Like the green revolution， 14 some call the gene revolution contributes to the problem of genetic uniformity—some say even more so 15 geneticists Can employ techniques such as cloning and 16 culture，processes that produce perfectly 17 copies．Concerns about the erosion of biodiversity，therefore，remain：Genetically altered plants，however，raise new 18 ， such as the effects that they may have on us and the environment．“We are flying blindly into a new 19 of agricultural biotechnology with high hopes，few constraints，and little idea of the potential 20 。”said science writer Jeremy Rifkin． A．manufacture
B．management
C．manipulation
D．maturity
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