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
2023-08-27
16
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.(29)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,(30)a kind of insects that cannot fly chew on the com 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.(31)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.(32)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.
29. What’s the main purpose of the talk?
30. What causes the corn plant to emit the chemical signal?
31. How do the bees protect the damaged corn plant?
32. What is the meaning of enhancing this natural response in plants?
选项
A、By flying in circles around a corn field.
B、By egging offspring who eats the insects.
C、By inspecting individual corn leaves.
D、By noticing the insect’s eggs.
答案
B
解析
文章中提到,在几天之后这些昆虫会死掉,因为蜜蜂的后代会吃掉它们,故答案为B)。
转载请注明原文地址:https://tihaiku.com/zcyy/2961668.html
相关试题推荐
[originaltext]Lastspring,SteveMcCarronhadhadenough.For10years—sinc
[originaltext]Lastspring,SteveMcCarronhadhadenough.For10years—sinc
[originaltext]TheOldCanadaRoadisalonglosttrailbetweentheCanadian
[originaltext]Facialexpressionscarrymeaningthatisdeterminedbysituat
[originaltext]Facialexpressionscarrymeaningthatisdeterminedbysituat
[originaltext]W:Ithinkifyouwanttogetsomeexcitementinyourlifeyouou
[originaltext]M:Todaytimehasgonebysoquickly!Doyouestimatehowlonga
[originaltext]M:Todaytimehasgonebysoquickly!Doyouestimatehowlonga
[originaltext]M:Ihaven’theardfromNancysincesheenteredmedicalschool.I
[originaltext]M:Ihaven’theardfromNancysincesheenteredmedicalschool.I
随机试题
A—trafficvolumeB—trafficjamC—trafficaccidentD—
Forthispart,youareallowed30minutestowriteashortessayentitledTheAd
C
妊娠28周末,子宫底高度约A.脐水平 B.脐上1横指 C.脐上3横指 D.
下列关于审计工作底稿归档期限与保存期限的相关说法中,错误的是( )。A、审计工作
男,20岁,长期患腹部疾病,多次剧烈腹痛,血浆呈奶油样乳白色,经1500r/mi
作为商品的房地产的价值可理解为()。A:只有使用价值 B:只有交换价值 C
男性,72岁,术后贫血合并有心功能不全,输入以下何种血细胞制品最恰当A.浓缩红细
Questions184-188refertothefollowing
下列因素影响贷款最低定价的有()。A.债务成本 B.股权成本 C.生产成本
最新回复
(
0
)