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】
A.manipulation
B.management
C.manufacture
D.maturity
第1题
如果用粗缆连接两台集线器,构建10BASE-T以太网,则两台机器的最远距离可达()。
A.500m
B.100m
C.700m
D.300m
第2题
如果用粗缆连接两台集线器,构建10BASE-T以太网,则两台机器的最远距离可达 ________。
A.500m
B.100m
C.700m
D.300m
第3题
如果用粗缆连接两台集线器,构建10BASE-T以太网,则两台机器的最远距离可达()。
A.100m
B.300m
C.500m
D.700m
第5题
如果用双绞线把计算机连接到集线器,构建100M以太网,则两台机器的最远距离可达()。
A.500m
B.100m
C.700m
D.300m
第9题
计算机学院下设三个专业,每个专业有一个局域网,每个局域网都是集线器连接的10Base-T以太网,为了使不同专业的计算机能够相互通信,现要用集线器将这三个局域网连接来,则新网的最大吞吐量是()。如果用交换机将这三个局域网连接起来,则新网的最大吞吐量是()
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