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
Widespread losses of plant species and varieties are eroding the foundations of agricultural productivity and threatening other
Widespread losses of plant species and varieties are eroding the foundations of agricultural productivity and threatening other
admin
2009-06-24
52
问题
Widespread losses of plant species and varieties are eroding the foundations of agricultural productivity and threatening other plant-based products used by billions of people worldwide. Plants provide us with irreplaceable resources. The genetic diversity of cultivated plants is essential lo breeding more productive and disease-resistant crop varieties. But with changes in agriculture that diversity is slipping away.
Biotechnology is no solution to this loss of genetic diversity. We are increasingly skillful at moving genes around, but only nature can create them. If a plant with a unique genetic trait disappears, there is no way to get it back.
The effects of plant loss extend far beyond agriculture. One in every four medicines prescribed in the U.S. is based on a chemical compound originally found in a plant. Worldwide, some 3.5 billion people in developing countries rely on plant-based medicine for their primary health care.
Loss of habitat from forest clearance for logging and agriculture, pressure from nonnative species and overharvesting have put one out of every eight plant species at risk of extinction. It is not just obscure or seemingly unimportant plants that are in trouble. Those that we rely upon most heavily are also declining. About two-thirds of all rare and endangered plants in the U.S. are close relatives of cultivated species. Crop breeders often turn to wild relatives of crops for key traits, like disease resistance, when they cannot find those traits in cultivated varieties.
Many medicinal plants are in trouble from overharvesting and destruction of habitat. The bark of the African cherry tree is widely used in Europe for treating prostate disorders, but the medicinal trade has led to severe depletion of the tree where it grows in the highlands of Cameroon and other Central African countries.
Since fewer than 1% of all plant species have been screened for bioactive compounds, every loss of a unique habitat and its species is potentially a loss of future drugs and medicines. Until recently, gene banks, botanical gardens and protected areas have been the first line of defense in maintaining the diversity of plant life. The world’s 1,600 botanical gardens collectively tend tens of thousands of plant species. But these conventional approaches need significantly higher levels of support. Many conservation facilities must scrape by on increasingly scarce funding, particularly those nm by national government.
Additional steps must be taken to reform policies and practices that work against plant diversity. Those who garner the benefits of plant diversity, such as agribusiness and pharmaceutical consumers, should acknowledge and support those who maintain it, including indigenous cultures and national gene banks.
Through benefit-sharing agreements, international conservation endowments and grass-root development projects attuned to the links between cultural and biological diversity, many options exist for supporting plant diversity rather than diminishing it.
选项
A、to supply more funding to gene banks, botanical gardens and protected areas.
B、to stop overharvesting and smuggling.
C、to save those seemingly unimportant plants.
D、to take further steps to revise policies and practices that hinder the keeping of plant diversity.
答案
D
解析
转载请注明原文地址:https://kaotiyun.com/show/4zHd777K
本试题收录于:
公共英语五级笔试题库公共英语(PETS)分类
0
公共英语五级笔试
公共英语(PETS)
相关试题推荐
Theshoppermanymakeacomplaintbecausehedislikescausingafuss.Ifthecustomerlosessomemoneybecauseofthefaultygo
ThefamousbankerhasconsiderableinfluencewiththePresidentoftheUnitedStates.
WhichofthefollowingstatementswouldBowlbysupport?WhichofthefollowingstatementsisNOTanargumentagainstBowlby’st
SolarequipmentSinceabout1800,nearthebeginningoftheIndustrialRevolution,coal,petroleum,andgashavebeenusedata
Whatdoesthephrase"turnthetablesontheirteachers"inPara.1mean?Whyhasthestudents’expectationoftheircoursesch
WhichofthefollowingisTRUEaccordingtoPara.1?Accordingtothepassage,whyhadtheratingagenciesrankedbothcompanie
A.DifferencesbetweentheoristsandotherscientistsB.TheyneedsocietyC.Theorists’charactersD.Theimportanceofunreasonabl
LifetimeemploymentintheJapanesecompanymeansthattheemployeeLifetimeemploymentinfluencesone’s
A.differsamonganimalspeciesB.topsychologicaldistanceC.begintoattackD.tophysiologicaldistanceE.distancebetweenana
A.differsamonganimalspeciesB.topsychologicaldistanceC.begintoattackD.tophysiologicaldistanceE.distancebetweenana
随机试题
下列属于执法活动的是
关于消化性溃疡下述哪种情况为手术适应证
黄疸形成的病理过程包括哪几项
A.肥达反应B.粪便培养C.血培养D.粪便镜检E.胆汁培养
某患者系肺虚久咳病人,兼有倦怠乏力之证,医生用六君子汤治疗后好转。此法符合中医哪种治则
房地产行政主管部门通过实施()对房地产中介服务人员进行管理。
贷款银行应根据贷款种类,在()个工作日内,告诉借款单位流动资金贷款审批结果。
张某向李某借款3万元,偿还期限为15个月,但未约定利息的支付期限,且事后未达成补充协议,该借款利息应在借款到期后一并支付。()
分析下述论证中存在的缺陷和漏洞,写一篇600字左右的文章,对该论证的有效性进行分析和评论。下面是奥林匹克食品公司(加工冷冻食品)呈送给公司股东的年度报告的一部分:在此期间,加工的成本下降了,因为企业已经学会了更加有效的工作。例如,在彩色胶卷
The______murdererignoredthepleasoftheweepingvictim.
最新回复
(
0
)