首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
(l)More and more of the world’s supply of seafood is coming from farms. (2)Although 80% of the world’s seafood comes from ma
(l)More and more of the world’s supply of seafood is coming from farms. (2)Although 80% of the world’s seafood comes from ma
admin
2017-02-18
47
问题
(l)More and more of the world’s supply of seafood is coming from farms.
(2)Although 80% of the world’s seafood comes from marine harvests, there is a major shift under way toward aquaculture now.
(3)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.
(4) "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.
(5)Biotechnology is contributing to high-yield aquaculture through transgenics—the transfer of genes from one species to another. Researchers introduce desirable genetic traits into fish, creating hardier stocks. For example, some species of fish have a protein that allows them to live in Arctic waters. By transplanting this "anti-freeze" gene into other species, researchers have created more fish that can survive in extremely cold water, according to Ag-West Biotech, Inc., in Saskatchewan, Canada.
(6)Biotechnologists are attempting to improve a wide range of genetic traits in fish used for aquaculture, developing fish that are larger and faster-growing, more efficient in converting feed into muscle, more tolerant of low oxygen levels in water, and better able to resist disease.
(7)Researchers also are seeking plant-based sources of food as a more efficient alternative to fishmeal. The use of plant protein on fish farms could take some of the pressure off wild fish stocks and address the problem of phosphorous pollution because plants do not contain high phosphorus levels. Wheat, canola, and canola oil are being used as alternative feed for aquaculture, according to Ag-West Biotech, Inc.
(8)While aquaculture produces a reliable source of protein, the industry is rife with environmental problems, asserts McGinn. Perhaps the biggest concern is water pollution: Fish waste and uneaten food accumulates at farm sites and can float directly downstream into water supplies. Farm-related nutrient wastes as well as nitrogen and phosphorus also promote the spread of algal "blooms" that deplete oxygen and kill marine life.
(9)Aquaculture is also an inefficient user of resources, McGinn charges. Fish farms need protein feed, and about 17% of ocean fish, an over harvested wild resource, becomes food for captive-bred fish. "An estimated five kilograms of oceanic fish reduced into fishmeal are required to raise one kilogram of farmed ocean fish or shrimp, representing a large net protein loss," says McGinn.
(10)Fish farming does not have to be an inefficient or polluting industry. McGinn predicts that many consumers will choose sustainably produced fish in the future, just as they prefer dolphin-free tuna today.
The author’s attitude towards aquaculture is _____.
选项
A、optimistic
B、negative
C、indifferent
D、uncertain
答案
A
解析
观点题。根据末段首句可以推断作者认为水产养殖业在利用率和防污染方面都将有所改善,因此可以看出作者对水产业是乐观的,因此选项A最恰当。
转载请注明原文地址:https://kaotiyun.com/show/I5JK777K
0
专业英语四级
相关试题推荐
WhichofthefollowingsentencesisComplexSentence?
Whichofthefollowingsentencesindicatessuggestion?
Whichofthefollowingsentenceshasbothdirectandindirectobject?
Thechildnodded,apparentlycontentwithhismother’spromise.Theunderlinedpartmeans______.
Aestheticthoughtofadistinctivelymodernartemergedduringthe18thcentury.Thewesternphilosophersandcriticsofthisti
Youwillseetoitthateverythingisreadybeforetheguestsarrive.Theunderlinedpartmeans______.
Thestatistics______thatlivingstandardsintheareahaveimproveddrasticallyinrecenttimes.
Benjaminwassweatingbulletsbythetimethepolicehadfinishedquestioninghim.Theunderlinedpartmeans______.
WhichofthefollowingprepositionalphrasesexpressesCONCESSION?
Manyremarkablepeopledealwithdepressionandanxietyallthetimebecausetheyseetheworlddifferentlythan______peopledo
随机试题
胃阴虚证的临床特征是
A.腹痛腹胀,暴泻如水,肛门灼热B.大便溏薄,时干时稀,排便不爽C.下痢脓血,里急后重,身热口渴D.腹满硬痛,大便秘结,日晡潮热E.大便燥结,艰涩难下,口干口臭肠热腑实证的临床表现是
16岁的甲与13岁的乙是好朋友,均为中学生。某日二人在住宅小区中玩耍,一辆某快餐店的送餐车前来小区送餐停放在路边。甲对乙说:“我最讨厌这家快餐店了,上次去吃快餐,钱没带够被老板骂了一顿,你悄悄去把车上的广告画弄脏,给我出出气。”乙遂找来一块废金属片在车厢上
为保护无行为能力的人和限制行为能力的人的合法权益而设立的代理形式是()
行政管理的基本依据是()。
Whatimpressedmemostwasthattheynever______.
《国家中长期教育改革和发展规划纲要(2010—2020年)》强调把促进学生成长成才作为学校一切工作的出发点和落脚点,这体现的工作方针是()。
查询设计器分为上下两部分,上半部分是表的显示区,下半部分是______。
Manyoftheelectricgoodswhichareadvertisedas______themodernwomantendtohavetheoppositeeffect.
A、clothes.B、shoes.C、pants.D、socks.B根据女士的话“lookatyourshoes”和“Youmustcleanthem.”可知,妈妈让Tom去洗鞋,故选B。
最新回复
(
0
)