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
45
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、all insects will be eliminated
B、all insecticides will be abandoned
C、super-bugs resistant to all poisons come out
D、scientists must invent new insecticides
答案
C
解析
转载请注明原文地址:https://kaotiyun.com/show/adDd777K
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
Ihavenoticedthatchildrenarenotevenbeingschoolinsocialgraces.AtaSundaybrunch,aclownwasmakingballoonanimals
Bythe1820’sintheUnitedStates,whensteamboatswerecommononwesternwaters,theseboatsweremostlypoweredbyenginesbu
Forcenturies,explorershaveriskedtheirlivesventuringintotheunknownforreasonsthatweretovaryingdegreeseconomican
Whatarethestudentsgoingtododuringthisclassperiod?
Whichofthefollowinglawisrelatedtoeducation?Howdidthestatecontroleducation?
Apsychologicalissuethatbegantobediscussedinthe1950swasthequestionofthemostappropriateageforsecondlanguagel
Whenwillshowersreachsouth-westEnglandandthesoutherncoastofWales?
Itcanbearguedthatmuchconsumerdissatisfactionwithmarketingstrategiesarisesfromaninabilitytoaimadvertisingatonl
In1971therewereabout3,700millionpeopleintheworld.Ifthepopulationwere【C1】______evenlyovertheearth’ssurfacet
Researchersinvestigatingbrainsizeandmentalabilitysaytheirworkoffersevidencethateducationprotectsthemindfromthe
随机试题
“人得自由,而必以他人之自由为界。”这告诫我们在政治参与中必须坚持()。
正色素性红细胞除见于正常人外亦可见于
对转氨基作用的叙述哪项是不正确的
病重、病危和需要严格卧床休息,生活不能自理者应给予
成人血清天门冬氨酸氨基转移酶的正常参考值范围是()。
Justaseachweddingcreatespotentialbusinessfordivorcelawyers,soeachengagementgivesinsurersachancetodrumupbusin
有下列程序 #include<stdio.h> #defineS1(x,y)x*y #defineS2(x,y)(x)*(y) main() {inta=2,b=5; printf("%d,%d,%d,%d",S1(a+b,a+
Afghanistan’sfirstmatchwillbeagainst______.
NovemberisDiabetesEyeHealthMonth,andthat’sjustoneofthereasonstotakeadvantageofEyeCareAmerica’sfreeprogram,d
WhichofthefollowingwaysofretiringinEnglandmentionedinthepassageisthefastestway?Atunnelis______.
最新回复
(
0
)