首页
登录
职称英语
[originaltext] Cultural controls are the oldest methods that have been used
[originaltext] Cultural controls are the oldest methods that have been used
游客
2023-08-24
49
管理
问题
Cultural controls are the oldest methods that have been used to manage pest populations. However, with the development of synthetic pesticides these controls were rapidly abandoned or de-emphasized and research on them was largely discontinued.(19)Today, we are going to talk about a natural way some plants respond to being invaded by pests. The plants react by emitting a chemical signal, which acts like a call for help. Let’s take corn plants for example. Sometimes,(20)a kind of insects that cannot fly chew on the corn leaves; when this damage happens, the plant releases a chemical scream that attracts a kind of bees. The bees respond to the signal by flying to the chewed on leave, and laying their eggs on the insects.(21)The insects die in the next few days as the bees’ offspring will eat the insects. Thus the corn plant prevents all its leaves from being eaten by the insects. This chemical scream is specific. It’s only released after the plant has damaged by the insects. A plant damaged in other ways does not give off the same signal, nor does undamaged plants. Cotton and probably many other plants use similar type of defense against pests.(22)By enhancing this natural response in plants, researchers might reduce, some day even eliminate the need for chemical pesticide, which can cause ecological damage. For example, scientists might breed plants for this screaming trait, or they might transplant specific genes to increase the release of the chemical signals.
19. What’s the main purpose of the talk?
20. What causes the corn plant to emit the chemical signal?
21. How do the bees protect the damaged corn plant?
22. What is the meaning of enhancing this natural response in plants?
选项
A、To describe ways pests can damage plants.
B、To examine the life cycle of corn plants.
C、To explain how corn plants develop.
D、To describe how a natural pesticide works.
答案
D
解析
文章在开头部分提到,本文要讲的是一些植物直接对抗入侵昆虫的自然方法,故答案为D)。
转载请注明原文地址:https://tihaiku.com/zcyy/2954515.html
相关试题推荐
[originaltext]Monarchbutterfliesareacommonsummersightinthenorthern
[originaltext]Monarchbutterfliesareacommonsummersightinthenorthern
[originaltext]MySpace,thesocialnetworkingwebsite,isdifferentfromoth
[originaltext]I’llstillbeworking,butthingswouldbedifferent.Withan
[originaltext]I’llstillbeworking,butthingswouldbedifferent.Withan
[originaltext]M:Whereareyougoing,Catherine?TodayisSaturday.W:Saturday
[originaltext]W:Whataday!I’mexhausted.M:Well,it’snotoveryet.W:Yeah
[originaltext]W:Whataday!I’mexhausted.M:Well,it’snotoveryet.W:Yeah
[originaltext]M:Iguesswe’llhaveahotsummeragain.W:Iknow.Lastsummer
[originaltext]M:Iguesswe’llhaveahotsummeragain.W:Iknow.Lastsummer
随机试题
[originaltext]W:Haveyoumanagedtoassemblethemachineyet?M:I’vebeenstudy
[originaltext]W:SothisistheInternet?M:Well,it’stheWorldWideWeb,whi
TheCrowBlackfoot,andSiouxtribes(traditionally)adorned(they)dwellingsan
期货交易者根据进入期货市场的目的不同,可分为()。A、套期保值者B、投机者C、个人D、会员A,B期货交易者根据进入期货市场的目的不同,可分为套期
解决问题的基本过程是( )。A.发现问题——理解问题——提出假设——检验假设
黄老师组织幼儿全班幼儿参观小学后,请每位幼儿将自己参观小学的感受、体会或愿望用图
以下哪些可以作为相对估值法的指标()。 Ⅰ.市盈率 Ⅱ.市净率 Ⅲ.
对表证较轻,喘咳较重的患者首选A:炙麻黄B:生麻黄C:麻黄绒D:蜜炙麻黄绒
作为主体的我对自己以及自己与周围事物的关系的意识称为()。
农产品具有的需求的特殊性包括()。A.农产品需求具有派生性 B.农产品需求价
最新回复
(
0
)