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
专升本
For many years, scientists couldn’t figure out how atoms and molecules(分子)on the Earth combined to make living things. Plants, f
For many years, scientists couldn’t figure out how atoms and molecules(分子)on the Earth combined to make living things. Plants, f
admin
2014-05-25
98
问题
For many years, scientists couldn’t figure out how atoms and molecules(分子)on the Earth combined to make living things. Plants, fishes, dinosaurs(恐龙), and people are made of atoms and molecules, but they are put together in a more complicated way than the molecules in the primitive ocean. What’s more, living things, that have energy and can reproduce on the Earth four billion years ago were lifeless.
After years of study, scientists figured out that living things, including human bodies, are basically made of amino acids and nucleotide(氨基酸与核苷酸)bases. These are molecules with millions of hydrogen(氢), carbon(碳), nitrogen(氮), and oxygen atom. How could such complicated molecules have been formed in the primitive soup? Scientists were stumped(难住).
Then, in 1953, two scientists named Harold Urey and Stanley L. Miller did a very simple experiment to find out what had happened on the primitive Earth. They set up some tubes and bottles in a closed loop(线圈), and put in some of the same gases that were present in the atmosphere four billion years ago: water vapor, carbon dioxide(二氧化碳), methane(甲烷), and hydrogen.
Then they shot an electric spark through the gases to simulate(模拟)bolts(闪电)of lightning on the ancient Earth, circulated the gases through some water, sent them back for more sparks, and so on. After seven days, the water that the gases had been bubbling(起跑)through had turned brown. Some new chemicals were dissolved in it . When Miller and Urey analyzed the liquid, they found that it contained amino acids—the very kind of molecules found in all living things.
Harold Urey and Stanley L. Miller did their experiment in order to______.
选项
A、find out what had happened on the Earth 4 billion years ago
B、simulate bolts of lightning on the ancient Earth
C、dissolve some new chemicals
D、analyze a liquid
答案
A
解析
文章第三段…Harold Urey and Stanley L.Miller did a very simpleexperiment to find out what had happened on the primitive Earth及第二句中的4billion years ago,由此可知这里的primitive Earth是指4 billion years ago,所以A为正确答案。
转载请注明原文地址:https://kaotiyun.com/show/gFUC777K
本试题收录于:
英语题库普高专升本分类
0
英语
普高专升本
相关试题推荐
Inour______,thelaboringpeoplearemastersofcountry,(social)
Itisbecausesheistooinexperienced______shedoesnotknowhowtodealwiththesituation.
WhenIsawthemessmypaperwasin,itwasobviousthatsomeone______it.
Althoughheisabsolutelyconvincedthattheplanwillwork,I’mstillabitskeptical______thefeasibility(可行性)ofit.
Isuggestedheshould______himselftohisnewconditions.
Thisreportsummedupthenewachievementsmadeinoureconomy,cultureandeducation.
A.We’vetakenstepstoensurethatitwon’thappenagain.B.BeingspecializedintheexportofChineseartandcraftgoods,we
Heborrowedthemoney_____hecouldfinishhiseducation.
A:Doyouhaveareservation,sir?B:【D1】______A:I’msorry.Therestaurantisfullnow.Youhavetowaitforabouthalfanho
随机试题
TheroadwhereIliveisverylongandverystraight.Thesurfaceismadeofwoodandtheroadiswelllightedatnight.Theres
简述实验诊断学的主要内容。
口服药物吸收差:脂溶性药物较易进入脑内:
以下属于浸出制剂的特点是
血中激素含量甚微,但其生理作用显著,这是因为
链霉素过敏性休克抢救静脉注射()
以下关于企业政策性搬迁的说法正确的有()。
ABC公司为商品经销公司。1999年度资产负债表有关资料为:“货币资金”年初数30000元、年末数150000元;“存货”年初数100000元;“应付账款”年末数15000元。其他资料为:购货采用赊购方式;本年共偿付购货款400000元;除购货外的其他费用
Yousingit.theseasonbetweenspringandautumn
Mikewastootiredtocontinueworking.Mikewassotired______hecouldn’tcontinueworking.
最新回复
(
0
)