EVOLUTION
THE ORIGIN OF LIFE
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Free oxygen could not have been present because there were no plants to produce it
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Free oxygen would have reacted with and destroyed organic molecules as they formed
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Free oxygen was not needed for a living cell to assemble from nonliving materials
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Free oxygen would have escaped from the early atmosphere into space due to high temperatures
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Detailed explanation-1: -Free oxygen would have reacted with and destroyed organic molecules as they formed. Why do many scientists believe that free oxygen was not present in early earth’s atmosphere?-Free oxygen could not have been present because there were no plants to produce it.
Detailed explanation-2: -Scientists think that lightning sparked chemical reactions in Earth’s early atmosphere. The early atmosphere contained gases such as ammonia, methane, water vapor, and carbon dioxide. Scientists hypothesize that this created a “soup” of organic molecules from inorganic chemicals.
Detailed explanation-3: -Oxygen, which takes hydrogen atoms from other compounds, interferes with the reactions that transform simple organic molecules into complex ones.
Detailed explanation-4: -Because of the absence of microbes on the primitive earth to digest them and the lack free oxygen in the primitive earth’s atmosphere to react with them, these molecules would have been stable.
Detailed explanation-5: -In the presence of water vapour, carbides reacted with hydrogen to form hydrocarbons. Such hydrocarbons were the first organic molecules. These further combined with oxygen and ammonia to produce hydroxy-and amino-derivatives, such as carbohydrates and proteins.