[单项选择]

More and more of the world’s supply of seafood is coming from farms.
Although 80% of the world’s seafood comes from marine harvests, there is a major shift under way toward aquaculture now.
Nearly 40% of salmon marketed today are raised in captivity, compared with 6% a decade ago. Forty percent of all clams, oysters, and mussels are produced in farm environments, along with 65% of freshwater fish. Between 1990 and 1996, fish-farming production rose from 12.4 million to 23 million tons worldwide, writes Anne Platt McGinn in an article for World Watch magazine.
"The fact that world seafood supplies continue to increase at all is due almost entirely to the phenomenal growth in aquaculture," says McGinn, a research associate at the World Watch Institute. Commercial aquaculture is driven by rising human population at a time when over harvested wild fish stocks are in decline and conventional farm production has leveled off.
Biotech
A. change feed into muscle more efficiently.
B. stand low oxygen levels in water.
C. tolerate extremely cold water.
D. grow larger and faster.

[单项选择]

More and more of the world’s supply of seafood is coming from farms.
Although 80% of the world’s seafood comes from marine harvests, there is a major shift under way toward aquaculture now.
Nearly 40% of salmon marketed today are raised in captivity, compared with 6% a decade ago. Forty percent of all clams, oysters, and mussels are produced in farm environments, along with 65% of freshwater fish. Between 1990 and 1996, fish-farming production rose from 12.4 million to 23 million tons worldwide, writes Anne Platt McGinn in an article for World Watch magazine.
"The fact that world seafood supplies continue to increase at all is due almost entirely to the phenomenal growth in aquaculture," says McGinn, a research associate at the World Watch Institute. Commercial aquaculture is driven by rising human population at a time when over harvested wild fish stocks are in decline and conventional farm production has leveled off.
Biotech
A. the human population is increasing fast.
B. the wild fish stocks are decreasing due to over fishing.
C. the cost of developing aquaculture is comparatively low.
D. there is no improvement in conventional farm production.

[单项选择]More and more of the world’s supply of seafood is coming from farms.
Although 80% of the world’s seafood comes from marine harvests, there is a major shift under way toward aquaculture now.
Nearly 40% of salmon marketed today are raised in captivity, compared with 6% a decade ago. Forty percent of all clams, oysters, and mussels are produced in farm environments, along with 65% of freshwater fish. Between 1990 and 1996, fish-farming production rose from 12.4 million to 23 million tons worldwide, writes Anne Platt McGinn in an article for World Watch magazine.
"The fact that world seafood supplies continue to increase at all is due almost entirely to the phenomenal growth in aquaculture," says McGinn, a research associate at the World Watch Institute. Commercial aquaculture is driven by rising human population at a time when over harvested wild fish stocks are in decline and conven- tional farm production has leveled off.
Biotechnology is contributing to high-yield a
A. the human population is increasing fast.
B. the wild fish stocks are decreasing due to over fishing.
C. the cost of developing aquaculture is comparatively low.
D. there is no improvement in conventional farm production.