Genetic engineering, the process of splicing (连接) together DNA from different organisms to create a preferred type of plant or animal, is a relatively new development in agriculturE.The first successful experiment was achieved in 1973. Despite of its recent emergence, 【S1】______ however, genetic engineering--particularly in the area of agriculture--has proliferated swiftly. Few Americans can now avoid genetically altered food altogether, but it's 【S2】______ estimated that modified ingredients are present in about two-thirds of the foods in American supermarkets. Supporters of genetic engineering have argued that this application of science allows farmers to grow crops more efficiently and to save money on pesticides and fertilizers. Fewer chemicals, they say, will be benefit for 【S3】______ the environment and reduce health risks for farm workers. Opponents of genetic engineering make the claim that scientists are tampering (损害) with matters that they know too little and essentially committing a crime 【S4】______ against naturE.It's impossible, they maintain, for people to see the possible consequences that genetic engineering 【S5】______ could wreak (带来) on the environment and on the health of human beings. 【S6】______ Greenpeace activists objected on farmers' use of corn that had been genetically modified to resist corn borers (玉米螟)--pests that were costing farmers up to a billion 【S7】______ dollars a year in mined crops. No one admitted that the genetic change had benefited the corn plants. But how would it impact upon the rest of the environment? Studies variously supported both sides of the argument 【S8】______ , and thus proved conclusivE.However, the protest cut to the heart of the genetic engineering controversy by 【S9】______ demonstrating what unprepared both the scientists and their opponents were to gauge (测量, 评估) the long-term effects of introducing changes into living beings. Perhaps, like most forms of technological innovation, genetic engineering will come to display both its benefits 【S10】______ and obvious drawbacks--many of which will be so apparent until mankind has pursued the experiment for some timE. 【S1】