首页
登录
职称英语
For many years, scientists couldn’t figure out how atoms and molecules combin
For many years, scientists couldn’t figure out how atoms and molecules combin
游客
2023-09-22
22
管理
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://tihaiku.com/zcyy/3035538.html
相关试题推荐
manytimes,buthestillcouldn’tunderstandit.A、HavingtoldB、Thoughhe
Accordingtotheobservationofsomescientists,wewillbeshortofenergyint
Scientistshavecreatedatomatothatcangrowonsaltywater.Theplantis
Interestingasdolphins(海豚)aretoscientists,itistheirintelligenceand
Interestingasdolphins(海豚)aretoscientists,itistheirintelligenceand
Interestingasdolphins(海豚)aretoscientists,itistheirintelligenceand
Anyway,evenifonewantedto,onecouldn’tputtheclockbacktoanearlierage
Whatdoscientiststhinkofdreams?Manyscientistsbelievethatdreamsare_____
Whatdoscientiststhinkofdreams?Manyscientistsbelievethatdreamsare_____
Whatdoscientiststhinkofdreams?Manyscientistsbelievethatdreamsare_____
随机试题
Noiseentersourearsaspowerfulwavesofmechanicalenergy.Scientistsmea
[originaltext]W:Let’sdosomething!Whydon’twegooutfordinnerorgodanci
CanWePlay?[A]Playisrapidlydisappearingfrom
关于建设工程竣工图的绘制和形成,下列说法中正确的是()。A:凡按图竣工没有变动
某饱和黏土层厚5m,其上为砂层,底部为不透水岩层,在荷载作用下黏土层中的附加应力
下列各项中,不属于企业所得税纳税人的是( )。A.在外国成立但实际管理机构在中国
为预防胎儿神经管畸形的发生,叶酸补充最好从( )开始。A.计划怀孕或可能怀孕前
(2013年真题)在城乡住户收支调查中,非抽样误差的可能来源有()。A.抽
关于信息化条件下的会计资料管理说法错误的是()。A、企业会计资料的归档管理,遵循
长期用于抗癫痫治疗时会引起牙龈增生的药物是A.苯琥胺 B.扑米酮 C.三甲双
最新回复
(
0
)