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
60
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
Yesterdayafternoonthey______(see)playingfootballintheclassroomandtold
Morethan2,000yearsago,thephilosopherSocrateswanderedaroundAthensa
狭窄场所必须选用I类手持式电动工具。
1923年,布朗斯特(Bmnsted)提出了酸碱质子理论,该理论认为NaHCO3
A.麻醉药品使用资格证书B.麻醉药处方C.麻醉药品购用印鉴卡D.麻醉药品经营单位
从购房者的实际经济承受能力出发,根据国际经验,月还款额一般不应超过家庭总收入的(
Thechangeinthatvillagewasmiraculou
乙酰半胱氨酸作用机制是A.增加痰液的黏稠度 B.与黏蛋白的双硫键结合,使其断裂
(2018年真题)商业银行在风险识别确定风险类型和风险点的基础上,对风险点出现的
下列关于平稳性随机过程,说法正确的是()。?A.任何两期之间的协方差值不依赖于
最新回复
(
0
)