题目内容
【C9】
查看答案
搜索结果不匹配？点我反馈
更多问题
【C7】
In nature, genetic diversity is created within certain【C8】______. A rose can be crossed with different kind of rose, but a rose will never cross with a potato. Genetic engineering,【C9】______usually involves taking genes from one species and inserting them into another【C10】______to transfer a desired characteristic. This could mean, for example, selecting a gene which leads to a production of a chemical with anti-freeze【C11】______from an arctic fish, and inserting it into a potato or strawberry to make it frost-resistant.【C12】______, then, biotechnology allows humans to【C13】______the genetic walls that separate species.
Like the green revolution,【C14】______some call the gene revolution contributes to the problem of genetic uniformity--some say even more so【C15】______geneticists can employ techniques such as cloning and【C16】______culture (培养), processes that produce perfectly【C17】______copies. Concerns about the erosion of biodiversity, therefore, remain. Genetically altered plants, however, raise new【C18】______such as the effects that they may have on us and the environment. "We are flying blindly into a new【C19】______of agricultural biotechnology with high hopes, few constraints, and little idea of the potential【C20】______," said science writer Jeremy Rifkin.
【C1】
【C2】
A．be carried overB．be freed fromC．be held upD．be drawn from
微信支付 
支付宝支付