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
23
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.
According to McGinn, aquaculture will most probably become _____ in the future.
选项
A、the major resource of seafood
B、a pollution-free industry
C、the major source of protein
D、an industry of sustainable development
答案
D
解析
推断题。末段末句中表明McGinn预测将来人们将选择可持续生产的鱼类,这就意味着水产养殖业将来应变成可持续发展的产业,才能满足将来人们的需求,因此本题应选D。
转载请注明原文地址:https://kaotiyun.com/show/b5JK777K
0
专业英语四级
相关试题推荐
Warning:Holdingacellphoneagainstyourearorstoringitinyourpocketmaybehazardoustoyourhealth.Thisparaphrase
Thereisnoquestionofsuccess.Theunderlinedwordmeans______.
Aestheticthoughtofadistinctivelymodernartemergedduringthe18thcentury.Thewesternphilosophersandcriticsofthisti
Itisanunderstoodfactthatwaterhelpsmobilizesolublenutrients,transportwastematerialsandregulatesbodytemperature.
Itisanunderstoodfactthatwaterhelpsmobilizesolublenutrients,transportwastematerialsandregulatesbodytemperature.
Itisanunderstoodfactthatwaterhelpsmobilizesolublenutrients,transportwastematerialsandregulatesbodytemperature.
Doctor’sOrdersYou’regoingtohavetochangeyourdietquiteconsiderably./Inparticular,you’regoingtohavetoavoid
[A]appears[B]case[C]distinguishes[D]dramatically[E]engaged[F]experience[G]lazy[H]noisy[I]pr
[A]appears[B]case[C]distinguishes[D]dramatically[E]engaged[F]experience[G]lazy[H]noisy[I]pr
A、Theproportionofrent.B、Asetofrules.C、Anagreementontheroomsize.D、Acookingschedule.B由句(3)可知,为了使合租计划能够取得成功,女士提出他们
随机试题
[2008年,第120题]价值工程的价值是()。
背景A公司参与远离所在地炼钢厂的机电安装工程总承包的投标,投标前做了如下工作:1.分析了招标文件工程范围,本工程含机械设备安装、电气及自动化系统安装、钢结构及非标准件制作安装、工业给水排水施工、防腐及保温工程、筑炉工程。并分析本公司施工技术力量
“包装物”的借方登记()。
现金在商业银行资产负债中属于()。
2017年8月,一家新开业的小型微利商业企业,为了拓展市场,从开业之日起至12月31日销售商品一律实行买一赠一活动,开业5个月销售商品共计取得不含税销售收入225万元,赠送商品的不含税市场价格为15万元,全部销售商品和赠送商品的成本为180万元,应扣除的税
在对债务重组进行账务处理时,债权人对债务重组的应收账款是否冲销其已计提的坏账准备,并不影响债务重组年度净损益的数额。 ( )
旅游安全事故主要包括()
已知数据表A中每个元素距其最终位置不远,为节省时间,应采用的算法是______。
Itwaslateintheafternoon,andIwasputtingthefinaltouchonapieceofwritingthatIwasfeelingprettygoodabout.Iwa
ImaginethatanIrishmarketingfirmisdoingresearchinyourcountry.Youhaveagreedtoparticipateinatelephoneinterview
最新回复
(
0
)