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
What have scientists discovered about plants and insects?
What have scientists discovered about plants and insects?
admin
2010-07-06
24
问题
What have scientists discovered about plants and insects?
Scientists have discovered that plants themselves produce many poisonous chemicals for defense against insects. But insects have developed ways of dealing with them and, in fact, have been eating plants for about 250 million years. Now insects are using these same mechanisms to deal with man-made poisons—insecticides. This is why resistance of insects to insecticides has developed so rapidly.
What should be done? Scientists studying the problem suggest that farmers use less insecticides. At the moment, farmers regularly spray crops as a precaution against problems that are caused by large numbers of pests. They should, instead, spray only where pests have actually been seen. Secondly, farmers could use a combination of two or three insecticides at once. To survive, the insects would need to become resistant to two or more insecticides at the same time.
The most surprising suggestion, perhaps, is that at certain times of the year, farmers should actually try to attract insects onto the crops they are trying to protect. The new insects will mate with those which survived from a certain kind of insecticide and will lessen the latter’s resistance to it.
Scientist hope that these and other measures will postpone the day when farmers and scientists will have to stand by while new super-bugs which may be resistant to all poisons invade our farms and devour our crops.
选项
A、Farmers use less insecticides.
B、Farmers spray only where posts have actually been seen.
C、Farmers could use a combination of two or three insecticides at once.
D、Farmers shouldn’t try to attract insects onto the crops.
答案
D
解析
转载请注明原文地址:https://kaotiyun.com/show/4dDd777K
本试题收录于:
公共英语四级笔试题库公共英语(PETS)分类
0
公共英语四级笔试
公共英语(PETS)
相关试题推荐
ThefailuretotalktoeachothercausesallofthefollowingEXCEPTBecauseyoungpeoplenowadaysdon’treadmuch,
Whenwerethefirstx-raysdiscovered?
Forthispart,youarerequiredtowriteacompositiononthetopic"OnDevelopingTourism".Youshouldwritecoherentlyandnea
Itcanbearguedthatmuchconsumerdissatisfactionwithmarketingstrategiesarisesfromaninabilitytoaimadvertisingatonl
PopulareducationinEnglandstartedasasocialwelfareaswellasaneducationalservice.RobertRaikes,whoopenedthefirst
In1971therewereabout3,700millionpeopleintheworld.Ifthepopulationwere【C1】______evenlyovertheearth’ssurfacet
Americanstodaydon’tplaceaveryhighvalueonintellect.Ourheroesareathletes,entertainers,andentrepreneurs,notschola
Americanstodaydon’tplaceaveryhighvalueonintellect.Ourheroesareathletes,entertainers,andentrepreneurs,notschola
Publicityoffersseveralbenefits.Therearenocostsformessagetimeorspace.Anadinprimetimetelevisionmaycost$250,00
Thereisonekindofpainforwhichnobodyhasyetfoundacure--thepainthatcomesfromtheendingofarelationship.Therela
随机试题
简要说明“语法的生成性”。
被称为原始文献,主要指原始论著、期刊论文、研究报告、专利说明书、学位论文等的文献是()
处方的意义,错误的一项表述是
证属()治法宜()
根据市场调查研究,获知某类房地产2003~2007年价格逐年上涨,分别为3500元/m2,3700元/m2,3950元/m2,4250元/m2,5500元/m2,运用平均发展速度法预测,则该类房地产2008年的趋势值大于4800元/m2。()[2
跟单员工作的起点是商务谈判的终点,终点是订单全部工作的完成。()
下列属于商业银行资产保全的手段有()。
眼手协调动作的出现是婴儿认知发展的重要里程碑。()
根据下列材料,回答问题。下列各项中,2012年1—6月同比增长率最大的是:
设f(χ)在[0,1]上连续,证明:存在ξ∈(0,1),使得∫0ξf(t)dt+(ξ-1)f(ξ)=0.
最新回复
(
0
)