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
Where does the plant grow?
Where does the plant grow?
admin
2009-03-16
28
问题
Where does the plant grow?
This morning I want to tell you about a recent scientific discovery dealing with the relation between plants and animals. This is about a desert shrub whose leaves can shoot up a stream of poisonous rosin for a distance of six feet. Do you think it would be safe from all attacks by insects? But a recant study has found one insect, a beetle, which can chew its way past the plant’s defense system by cutting the main vein that delivers the poison to the leaves. This vein cutting is jut one method the beetles used to prepare a safe meal. Then they simply eat between the veins of poison. In the past, scientists who studied insect adaptation to plant defenses have focused on chemical responses. It is only after a beetle has survived several encounters with the plant’s resin that it learns how to avoid the poison by chewing through the resin transporting veins on the next leaf it eats and thus gives itself a meal. However, it can take a beetle an hour and a half of careful vein cutting to prepare a small leaf that takes it only a few minutes to eat. So, though the method is effective, it’s not very efficient.
选项
答案
1.5 hours.
解析
转载请注明原文地址:https://jikaoti.com/ti/enBsFFFM
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
Note:AnswereachquestionbychoosingA,B,CorDandmarkitonANSWERSHEET1.Somechoicesmayberequiredmorethanonce.
AccordingtotheAmericanAcademyofDermatology,anestimated10to50millionpeopleinthiscountryhaveanallergicreaction
What’stheaverageincreaseperyearofforeignstudentpopulationintheperiodbetween1985and1990intermsofpercentage?
What’stheaverageincreaseperyearofforeignstudentpopulationintheperiodbetween1985and1990intermsofpercentage?
What’stheaverageincreaseperyearofforeignstudentpopulationintheperiodbetween1985and1990intermsofpercentage?
What’stheaverageincreaseperyearofforeignstudentpopulationintheperiodbetween1985and1990intermsofpercentage?
Whatdoesthelecturemainlyconcern?
Whatdoesthelecturemainlyconcern?
随机试题
腰上三角底部腱膜的深面有3条神经,自上而下排列为()
学前美术教育活动的评价包括:_______;活动内容和工具材料;_______;活动效果。
学在官府
独资经营
患者,男,36岁。7天前发热、咽疼.应用抗生素治疗无效,颈部浅表淋巴结肿大,咽部充血。扁桃体Ⅱ度肿大,下肢少许瘀斑。白细胞15.8×109/L,原始细胞0.60,血红蛋白80g/L,血小板34×109/L。为明确诊断应做的检查是()
下列哪项不是钙拮抗剂的适应证
投资者必须在银行间市场或证券交易所设立账户,才能买卖的国债是()。
【B1】【B2】
LastyearatthistimeJessicaAndersonwasworkinginChicago,oneofthecoldestcitiesintheUnitedStates.Nowsheisworki
Youwillhearfiverecordings.Foreachrecording,decidewheretheconversationhappened.Writeoneletter(A-H)nexttothenumb
最新回复
(
0
)