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
2015-03-13
76
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/giUC777K
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
Thegoals,hopes,fearsanddesires______widelybetweenmenandwomen,betweenrichandpoor.
Inyourfirstdaysattheschoolyou’11begivenatesttohelptheteacherto______youtoaclassatyourlevel.
Onesummernight,onmywayhomefromworkIdecidedtoseeamovie.Iknewthetheatrewouldbeair-conditionedandIcouldn’t
MoviesarethemostpopularformofentertainmentformillionsofAmericans.Theygotothemoviestoescapetheirnormaleveryd
Environmentalgroupsintendto______thepressureuntilthegovernmentchangesthelaw.
______marketingisconcerned,itisbettertohaveameetingwiththesalesmanagers.
Caffeineisachemicalsubstancethatstimulatesthenervesofthebody.Drinkingcoffeetendstomakepeoplealittlebitmore
_____inhumansocietyisnotpossibleunlesspeoplelearntorespectthosewhosewaysoflife,customsandformsofsocietyare
Thisyeartheworld’spopulationtickedoverto7billion.【R1】______Theyforecastdramaticchangesunlesssignificantstepsare
随机试题
杜陵叟白居易杜陵叟,杜陵居,岁种薄田一顷余。三月无雨旱风起,麦苗不秀多黄死。九月降霜秋早寒,禾穗未熟皆青干。长吏明知不申破,急敛暴征求考课。典桑卖地纳官租,明年衣食将何如!剥我身
Word2010的视图不包括________。
交通性鞘膜积液与腹股沟斜疝的主要鉴别是
慢性盆腔炎最主要的病变部位是
非法拆阅邮件或窃听公民电话等通讯内容的行为侵犯了公民下列选项中的哪项权利?()
某铁路工程项目合同段内有轨道、隧道、路基、桥涵工程,合同工期25个月,铺轨期限为开工后第17~23个月。项目经理部制定施工部署时,按里程将管区平均划分为三个工区,假设该施工单位拥有轨道施工架子队1个、路基施工架子队3个、桥涵施工架子队4个、隧道施工架子队
商品化会计软件与定点开发会计软件的最大区别在于()。
商业银行的()是指银行业务发展的未来方向及实际的执行计划,因经济环境及科技发展的转变做出的战略改变对银行经营的影响,是银行的策略制定和实施过程中失当,或未能对市场变化做出及时的调整,从而影响到现在或未来银行自身的盈利、资本、信誉和市场地位的风险。
TradeUnions1.Somescholarshaveassociatedtradeunionswiththemedievalcraftguilds(中世纪的行会),butthereareimportantdif
Thereweretwowidelydivergentinfluencesontheearlydevelopmentofstatisticalmethods.Statisticshadamotherwhowasdedi
最新回复
(
0
)