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
2016-11-13
29
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.
Scientists figured out that human bodies are basically made of______.
选项
A、amino acids
B、hydrogen, carbon, nitrogen and oxygen atoms
C、molecules
D、water vapor, ammonia, carbon dioxide, methane and hydrogen
答案
A
解析
文章第二段第一句:…scientists figured out that living things,includinghuman bodies,are basically made of amino acids and nucleotide bases,科学家断定包括人在内的人物都是由氨基酸和核苷酸为基础构成的。
转载请注明原文地址:https://kaotiyun.com/show/UuHC777K
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
Forthispart,youareallowed30minutestowriteacompositiononthetopic"Sounds"inthreeparagraphs.Youhavebeengiven
Thepoorgirlcouldn’t______fromhertearsanymorewhenhermothershowedup.
Whenamanisdrivingacarforlongdistancesalongamainroadormotorway,twoofhisproblemsaretokeepthecaratafairl
______theadvancesofscience,thediscomfortsofoldagewillnodoubtalwaysbewithus.
Somescientiststhinkthatthereisnobetter______formother’smilk.
ThedayafterThanksgivingisconsideredthefirstdayoftheholidayshoppingseasonintheUnitedStates.Itevenhasaname—
A、Olympicathletesintraining.B、Citylifeguards.C、Studentswhoarepoorrunners.D、StudentstakingafitnesstestD
Ifyou______intakingthisattitude,we’llhavetoaskyoutoleave.
Mr.Smithusedtoworkthenight______inapowerplant.
随机试题
腭的大部分来自
某人计划5年末购置一辆价格为75000元的汽车,故每年年末向银行等额存款一次,已知年利率为5%,则此人每年末等额存款应为()元。
第二审法院对上诉案件经过审理后所作出的下列裁判中,正确的有()。
关于绩效薪酬,下列说法错误的是()。
信息技术教学中需注意的问题。
班级管理的主要功能是()。
下列关于一地址指令的说法正确的是()。
在设计一个要求具有NAT功能的小型无线局域网时,应选用的无线局域网设备是()。
某学生成绩管理系统的“主窗体”如下图左侧所示,点击“退出系统”按钮会弹出下图右侧“请确认”提示框;如果继续点击“是”按钮,才会关闭主窗体退出系统,如果点击“否”按钮,则会返回“主窗体”继续运行系统。为了达到这样的运行效果,在设计主窗体时为“退出系统”按
Formostpeople,fatisaburden.Itdoesntreallymatterwhereitappears,wejustdon’twantit.Butitturnsoutthatourbo
最新回复
(
0
)