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
For many years, scientists couldn’t figure out how atoms and molecules combined to make living things. Plants, fish, dinosaurs,
For many years, scientists couldn’t figure out how atoms and molecules combined to make living things. Plants, fish, dinosaurs,
admin
2014-10-09
70
问题
For many years, scientists couldn’t figure out how atoms and molecules combined to make living things. Plants, fish, dinosaurs, 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 have energy and can reproduce, while the chemicals on the Earth 4 billion years ago were lifeless.
After years of study, scientists figured out that living things, including human bodies, are basically made of amino acids, nucleotide bases, lipids and water. How could such complicated molecules have been formed and have started to interact in the primitive soup? Scientists were stumped.
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, and put in some of the same gases that were present in the atmosphere 4 billion years ago — water vapour, ammonia, carbon dioxide, methane, and hydrogen.
Then they shot an electric spark through the gases to simulate bolts of lightning on the ancient Earth, circulated the gases through some water, sent them back for more sparks, and so on. After several days, the water that the gases had been bubbling through 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.
选项
A、4 billion years ago.
B、After seven days.
C、Many years ago.
D、In 1953.
答案
D
解析
转载请注明原文地址:https://kaotiyun.com/show/QdYK777K
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
WhatisthepurposeofpeopletohaveThanksgivingDay?Peoplesetasidethedayeachyearfor______toGodforourblessings.
A、South.B、North.C、West.D、East.B根据…thebedroomfaceseastandthelivingroomnorth.可知,客厅朝向北。
Igavethecarathorough(inspect)______beforebuyingittomakesurethatitwentwell.
Conversation:Thefollowingaretwobusinessletters.Afterreadingthem,youshouldgivebriefanswerstothe5questions(No.
Noagreementwasreachedinthediscussionasneithersidewouldgivewayto______.
I’mlookingforwardtoourfurther(cooperate)______inthefuture.
Pleasefeelfreetotellus______youthinkaboutourprogramsothatwecanbenefitfromyourviewsandexperience.
Manyagirl(be)______disappointedafterseeingthedrama.
Somepeoplebelievethatyouhavetobeaspecialkindofpersontosellaproduct.Butalthoughitisclearthatasuccessfuls
A、Bycheck.B、Incash.C、Bycreditcard.D、Bymail.A题目问支付情况。对话最后女士提到了付款方式,女士问:“我们用支票付款可以吗?”男士回答“没问题”。所以正确答案为A项。
随机试题
未成年犯罪嫌疑人、被告人享有哪些特别的诉讼权利?
hadtolook,mustlook,shouldhavelooked,after,on,atCareydidn’tgotothepartylastnightbecauseshe____________the
A、16岁以后B、3~6个月C、1~2岁D、4~6岁E、9~12岁;唇腭裂序列治疗程序中语言评价及语言治疗时间为
垃圾填埋场大气环境影响预测及评价的主要内容是()。
下列属于先期违约的是()。
“经营单位”栏:()。“标记唛码及备注”栏:()。
二次积分写成另一种次序的积分是()
下列合法的字符型常量是()。
Thecurrentpoliticaldebateoverfamilyvalues,personalresponsibility,andwelfaretakesforgrantedtheentrenchedAmerican
Inthepoem,hedepictedthehappy________ofgirlsplayingonaswinginearlyspring.
最新回复
(
0
)