首页
登录
职称英语
[originaltext] Scientists have observed that plants themselves produce many
[originaltext] Scientists have observed that plants themselves produce many
游客
2024-02-02
13
管理
问题
Scientists have observed 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—insecticide. This is why resistance of insects to insecticide has developed so rapidly. What should be done? Scientists studying the problem suggest that farmers use less insecticide. 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 insecticide at once. To survive, the insects would need to become resistant to two or more poisons at the same time. The most surprising suggestion, perhaps, is that, at certain times of the year, farmers should actually try to attract new 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.
Scientists 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 our poisons invade our farms and devour our crops.
19 What does the speaker say about plants?
20 What is mentioned as one of the suggestions raised by scientists?
21 What is the most surprising suggestion scientists give?
选项
A、There are 250 million plants eaten by insects.
B、There are fewer plants than 250 million years ago.
C、They have their way of guarding against insects.
D、They have a better immune system than before.
答案
C
解析
短文开头就说到,科学家发现植物自身可以产生许多有害的化学物质来抵御昆虫的侵害,即植物自有抵制昆虫侵害的方法,C与此含义相符,故正确。
转载请注明原文地址:https://tihaiku.com/zcyy/3416167.html
相关试题推荐
[originaltext]M:Didyoureallygiveawayallyourfurniturewhenyoumovedint
[originaltext]M:Didyoureallygiveawayallyourfurniturewhenyoumovedint
[originaltext]M:Didyoureallygiveawayallyourfurniturewhenyoumovedint
[originaltext]M:IjustreceivedanE-mailfromoneofmyformerclassmates.I
[originaltext]M:IjustreceivedanE-mailfromoneofmyformerclassmates.I
[originaltext]M:IjustreceivedanE-mailfromoneofmyformerclassmates.I
[originaltext]M:IjustreceivedanE-mailfromoneofmyformerclassmates.I
[originaltext]M:IjustreceivedanE-mailfromoneofmyformerclassmates.I
[originaltext]M:IjustreceivedanE-mailfromoneofmyformerclassmates.I
[originaltext]CountyfairsareatraditioninNewEnglandtowns.Theyoffer
随机试题
中国某大豆进口商,在5月份即将从美国进口大豆,为了防止价格上涨,2月10日该进口商在CBOT买入40手敲定价格为660美分/蒲式耳的5月大豆的看涨期权,权利金为
下列对有机建筑的解释,哪一条不是美国著名建筑大师赖特的论述:()A.有机建筑
及时反馈是促使传播进行下去的A.突出条件 B.显著要素 C.重要条件 D.
细集料筛分试验应进行二次平行试验,以平均值为测定值。若二次试验所得的细度模数之差
患者,女性,54岁,于家中搬家具时突然出现腰部剧烈疼痛,且双下肢有放射样麻木及疼
简述云盘的概念及特点。
法国作曲家奥涅格的管弦乐曲《太平洋231》描绘的音乐形象是() A.大
箱涵顶进挖运土方,两侧应欠挖( )mm,钢刃脚切土顶进。 A、80 B、
在压片过程中,常出现裂片、松片或崩解迟缓等各种原因。下列哪些是造成裂片的原因
确诊肺结核的主要依据是( )。A.X线检查 B.痰中找到结核分枝杆菌 C.
最新回复
(
0
)