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
Isn’t it surprising that scientists have a better understanding of how many stars there are in the galaxy (银河系) than how many sp
Isn’t it surprising that scientists have a better understanding of how many stars there are in the galaxy (银河系) than how many sp
admin
2013-02-05
50
问题
Isn’t it surprising that scientists have a better understanding of how many stars there are in the galaxy (银河系) than how many species there are on Earth? Their estimates of global species diversity vary from 2 to 100 million species. Most people agree on an estimate of somewhere near l0 million and yet only 1.75 million have actually been named. Current knowledge of species diversity is limited. This problem becomes more serious because there is a lack of a central database or list of the world’s species.
New species are still being discovered — even new birds and mammals(哺乳动物). On average, about three new species of birds are found each year, and since 1990, 10 new species of monkeys have been discovered. Other groups are still far from being completely described: an estimated 40 percent of freshwater fishes in South America have not yet been classified.
Scientists were started in 1980 by the discovery of a huge diversity of insects in tropical forests. In one study of just 19 trees in Panama, 950 new species of beetles were discovered.
As scientists begin investigating other little-known ecosystem, like the soil and the deep sea, "surprising" discoveries of species become commonplace. There is nothing strange about this, though, since as many as a million undescribed species are believed to live in the deep sea. And one gram of a small-sized piece of land might hold 90 million bacteria(菌类) and other microbes (微生物). How many species these communities contain is still anyone’s guess.
Which of the following best reveals the main idea of the passage?
选项
A、Surprising discoveries of new species are commonplace.
B、The mystery of the deep sea and the soil remains to be uncovered.
C、Knowledge of global species diversity is still limited.
D、Estimates of global species diversity vary among scientists.
答案
C
解析
主旨大意题。通读全文可以发现,作者一直在介绍地球物种的局限性。因此C选项最符合题意,故选C。
转载请注明原文地址:https://jikaoti.com/ti/XR3MFFFM
本试题收录于:
大学英语三级A级题库大学英语三级分类
0
大学英语三级A级
大学英语三级
相关试题推荐
A—AgriculturalEconomicsB—AnimalScienceC—BusinessLawD—EngineeringPhysicsE—MarketingS
Eagerlywatchingthechild’slearningofnewskills______.Inmoralmatters,parentsshould______.
Whatchancedoyouhaveonyourwaytothegate?Youcanbuysomethingat______.
A、Becausehewaslate.B、Becausehedidn’tpasstheEnglishtest.C、Becausehedidn’tpassthemathtest.D、Becausehismathtea
A—hospitalityB—orderdishesC—specialtyD—spiceE—beverageF—champagneG—sodawa
A、$116B、$150C、$115D、$126C本题为数字计算题。听懂对话和问话的基本内容即可确定正确答案是选项C。
Itissaidtheconferenceis______(hold)inthishallnextmonth.
AttheinternationalterminalforNorthwestAirlinesatJohnF.KennedyInternationalAirportinNewYork,passengerswaitedupto
I’mgladtosaythathe’salreadyfinished______50%ofthebookinthesepastthreedays.
SoonaftertheSeptember11attacks,theproperty’sownershadconsideredtheideaofrebuildingthetowersexactlyastheyhad
随机试题
在制药生产企业管理中A、不准投入生产B、不得流入下工序C、不准出厂D、不得进行另一品种或不同规格的同品种生产E、不得存放私人杂物不合格原辅料
既能发表解肌,又能升阳止泻的药物是
海关将从事加工贸易的企业分为A、B、C、D四种类别,实施动态分类管理。下列属于D类企业条件有()。
价值规律的作用主要表现在()。
某个班级要组织一项活动,主要由3个人负责具体活动安排:(1)如果李雪负责组织参与人员工作,那么她就要负责活动的路线安排工作,同时做好活动的时间安排工作;(2)只有负责活动的路线安排工作或者活动的时间安排工作,王东才不负责活动的宣传工作;(3)张丽要么
[*]
局域网从介质访问控制方法的角度可以分为两类:共享介质局域网与______局域网。
Althoughtherehadbeenvarioussmallcamerasdeveloped,itwasnotuntilGeorgeEastmanintroducedtheKodakin1888thatthem
Whataretheimportantqualitiesofagoodsonordaughter?Havethesequalitieschangedorremainedthesameovertimeinyour
SunlightisagreatsourceofvitaminDinmostoftheworld.Yeta(an)【C1】______numberofexpertsthinkthatmanypeoplearen’t
最新回复
(
0
)