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
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、
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、
admin
2013-09-26
53
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、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://kaotiyun.com/show/c927777K
0
大学英语六级
相关试题推荐
A、It’stoowindy.B、Thepeoplethereareterrible.C、Theairispolluted.D、Thebeachesaredirty.C
WhensoccerofficialsintheUnitedStateslearnedtheirnationwasselectedto【B1】______the1994worldCupfinals,theyreacte
A、Mentalhospitals.B、Prisons.C、Privatehomes.D、Anyresidentialareas.CWhichofthefollowingwasmentionedasasiteforthe
Nowadays,incominggenerationsreallyrelynowonthepowerofthe"Internet"whenitcomestosearchingforinformation.Justt
Methodsofstudyingvary;whatworks【C1】______forsomestudentsdoesn’tworkatallforothers.Theonlythingyoucandoisex
A、Becausepeoplemighthavetomigratetheresomeday.B、Becauseitisverymuchliketheearth.C、Becauseitiseasiertoexplor
A、Theyarefast-growing.B、Theyarenottrust-worthy.C、Theyareprofitable.D、Theyaresetupbydepartmentstores.B女士说阅读了一篇关
SuggestionsforYourWorkAnnieisalongtimesecretary/receptionistfortwoseniorvicepresidentsatabigcompany.They
A、Totalkwithsomeoneorwithoneself.B、Tohavealongandgoodrelaxation.C、Todomoreaerobicexercises.D、Totakemoreant
A、ToinvestigatethecausesofAIDS.B、ToraisemoneyforAIDSpatients.C、TorallysupportforAIDSvictimsinAfrica.D、Todra
随机试题
关于卵巢成熟畸胎瘤的描述,不正确的是
胎盘早期剥离的诊断主要是依靠下列哪项
队列研究中,确定样本含量时,与下列哪项无关
某护士用下排气式高压蒸气灭菌锅进行灭菌,8:35am锅内压力达到所需数值,其后一直维持在103~137kPa之间,结束灭菌的正确时间是()。
管网灭火系统应设()启动方式。
在学习成败归因影响学习动机的诸因素中,激励作用最大的是()。
钢琴组曲《镜》是_________创作的。
邓小平同志科学世界观最鲜明的特征是
文涵是大地公司的销售部助理,负责对全公司的销售情况进行统计分析,并将结果提交给销售部经理。年底,她根据各门店提交的销售报表进行统计分析。打开“计算机设备全年销量统计表.xlsx”,帮助文涵完成以下操作:将工作表平均单价中的区域B3:C7定义名称为“商
Whatisthemainpurposeoftheannouncement?
最新回复
(
0
)