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】