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
Trees in rainforests have broad leaves. The advantage is______.
Trees in rainforests have broad leaves. The advantage is______.
admin
2010-07-06
36
问题
Trees in rainforests have broad leaves. The advantage is______.
Plants are adapted to the climate they live in for the most part. Trees in rainforests have broad leaves, shaped to encourage the heavy rain to run off the leaves. The large leaves encourage transpiration so the plants don’t overheat. In very dry climates plants may develop an ability to store water, such as the cactus, which also has its leaves reduced into tiny spines which reduce transpiration to almost nothing so its precious water is conserved. At the first sign of drought, plants close their leaf pores to prevent wilting and slowing down growth so that they need less water. Coniferous plants also have small spiky leaves so that they don’t lose too much water during the frozen winters. Grasses roll their leaves into tubes to protect their leaf pores from the drying effect of the wind. Tropical air plants have moisture sensitive plugs attached to their leaf pores which are pulled down over the pores, sealing them to hold in moisture, by the contraction of the stalks in dry weather.
Plants are affected by strong winds which make them grow thicker and more stunted stems to strengthen and prevent themselves from being blown over. A special sort of strong wood called "reaction wood" grows on the leeward side of tile wind. Plants are also susceptible to waterlogging and freezing and many plants have developed complex mechanisms and adaptations to protect themselves from disasters.
选项
A、to accept more sun light
B、to encourage the heavy rain to run off the leaves
C、to shade their roots
D、to hide their trunk
答案
B
解析
转载请注明原文地址:https://kaotiyun.com/show/I1Dd777K
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
TodayTVaudiencesallovertheworldareaccustomedtothesightofAmericanastronautsintip-topcondition,withfairhair,c
Youwillreadaquestionwhichsays,"Whichisabettersourceofnews—newspaperorTV?"Writeanarticleforthenewspaper
Howcanforeign-traineddoctorsgetapprovedfromtheEducationalCommissiontocompletearesidencyintheU.S.?WhathaveAm
Apsychologicalissuethatbegantobediscussedinthe1950swasthequestionofthemostappropriateageforsecondlanguagel
TheU.S.SupremeCourthasforbiddenprayersinpublicschools,butmanyAmericansclingtotheideathattheireducationalsys
TheU.S.SupremeCourthasforbiddenprayersinpublicschools,butmanyAmericansclingtotheideathattheireducationalsys
Ouranalysisthereforesuggeststhattherealproblemfacingtheblackcommunityliesintheeducationalobstaclespriortothe
Ithasbeennecessarytoreferrepeatedlytotheeffectsofthetwoworldwarsinpromotingallkindsofinnovation.Itshouldb
Governmentsthroughouttheworldactontheassumptionthatthewelfareoftheirpeopledependslargelyontheeconomicstrength
Governmentsthroughouttheworldactontheassumptionthatthewelfareoftheirpeopledependslargelyontheeconomicstrength
随机试题
下颌颊侧翼缘区属于
患者男性,32岁,体重60kg。患肠梗阻,发病后3天住院,自诉口渴无力,尿少面黄,一般情况较差,体温38℃,血压75/60mmHg,精神萎靡,唇舌干燥,眼窝凹陷,膝反射减弱,入院后行胃肠减压,抽出消化液700ml,患者应补充10%KCl多少
直肠癌病人粪便可呈()
编制SF6互感器安装预算时可参照同电压等级的油浸式定额,人工定额乘以系数1.1。
商业银行在经营活动中要坚持的“三性”原则不包括()。
在进行滴定分析时,酸式滴定管的准备有三个步骤,即()、对滴定管进行洗涤和用标准溶液润洗滴定管。
马克思主义认为,世界的真正统一性在于它的()。
四名运动员参加4×100米接力,他们100米速度分别为v1,v2,v3,v4。不考虑其他影响因素,他们跑400米全程的平均速度为()。
建立一个学生信息表student,要求它由学号sno,姓名sname,性别sex,年龄age,4个属性组成,其学号属性惟一,学号、姓名字段不能为空。下列语句正确的是
Universitiesaredevisinganewnationaltestforgraduatestohelpemployersselectrecruits.Themovefollows【C1】______thatd
最新回复
(
0
)