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
2019-11-21
46
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,including human 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/wbxC777K
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
A、Havingamealatahotel.B、Picnickingintheopenair.C、Preparingdinnerathome.D、Travelingbytrain.B
我理所当然地认为,你会来跟他谈这件事的。
A、Becausehewasgivinghisattentiontothecharacters.B、Becausehewasbusyappreciatingtheplot.C、Becausehewasupsetby
Tokyoisoneofthoseplacesthatyoucanloveandhateatthesametime.InTokyotherearealwaystoomanypeopleinthep
Takingpartinfree-timeactivitieswithothershelpsustomeetoursocialneedswhileatthesametimedistractingusfromour
A.Tomakeaninquiryaboutouroranges,arepresentativeoftheJapanesecompanypaidusavisit.B.Ifyourpricesarefavorab
Manyaman______lifeismeaninglesswithoutpurpose.
"Whydidn’tTomcometothepartylastnight?""He______nothavewantedtoseeme."
Anylivingthing______diewithoutthesun.
Dadhadablackcomb.HeboughtitwhenhemarriedMum.Everynight,hewould【C1】______mehiscombandsay,"Goodgirl,helpDad
随机试题
内径54.64mm,壁厚9.19mm,外径(),API型钻杆(D55类)的抗扭屈服极限是18716N.m。
肺炎球菌在肺泡内繁殖,通过哪一途径扩散而致肺段或肺叶实变
蛔虫病的辨证纲领是
在精神分析中,治疗师会潜意识恋慕或憎恨患者.称为
某采石厂开采地点距国道大桥16.7m,1987年采矿由村办企业转为乡镇企业,王某某承包经营该厂,破碎车间由李某某承包并作为负责人兼安全员。1989年7月,由于该采石厂在出事故地点的开采处已经形成明显伞檐,王某某发现李某某在原开采点和出事地点两处之间进行
一般资料:张某,女,28岁,在职教师(工作半年),单身,身高1.66米,五官端正。家中有一小2岁的妹妹,父亲为一大专院校教师,母亲为幼儿园教师,父母关系长期不和。从小喜爱读书,成绩优秀,高中毕业考人某重点大学,本科毕业后考研两次,硕士研究生毕业后去外地某中
关于新时代西部大开发的新格局,下列做法错误的是()。
张某死后,遗产包括1张100元的存折,l台电视机和一些旧家具。张甲、张乙、张丙是张某的三个儿子。因无遗嘱,故三人经协商后,张甲继承了存折,张乙继承了电视,张丙继承了旧家具,一段时间后,王某向张乙出示了自己将电视借给张某的借条,张乙将电视还给王某。据此,下列
求空间曲线积分J=∫Ly2dx+xydy+xzdz,其中L是圆柱面x2+y2=2y与平面y=z一1的交线,从x轴正向看去取逆时针方向.
Therelationshipbetweenformaleducationandeconomicgrowthinpoorcountriesiswidelymisunderstoodbyeconomistsandpoliti
最新回复
(
0
)