Before there was any life on earth, which gas was absent from earth’s ancient atmosphere?
Biology · High School · Mon Jan 18 2021
Answered on
Correct answer is oxygen.
Earth's original atmosphere was rich in methane, ammonia, water vapour, and the noble gas neon, but it lacked free oxygen.
According to Oparin, the atmosphere of primitive earth was reducing because the hydrogen atoms were most numerous and most reactive. Large quantities of hydrogen gas, nitrogen gas, carbon dioxide, methane, water vapour and ammonia were present but free oxygen was not present in significant amount.
Hence, oxygen was absent during the formation of earth.