Question

According to one of the most accepted theory the earth atmosphere before any life had originated consisted of water vapour, hydrogen, $N{H}_3$ and

• A. Methane
• B. Nitrogen
• C. Oxygen
• D. Carbondioxide

Answer 1

The correct option is A Methane

There is abundant evidence of major volcanic eruptions 4 billion years ago, which would have released carbon dioxide (CO${}_2$), nitrogen (N${}_2$), hydrogen sulfide (H${}_2$S), and sulfur dioxide (SO${}_2$) into the atmosphere.

The first atmosphere would have consisted of gases in the solar nebula, primarily hydrogen. In addition, there would probably have been simple hydrides such as those now found in the gas giants (Jupiter and Saturn), notably water vapor, methane and ammonia. As the solar nebula dissipated, these gases would have escaped, partly driven off by the solar wind.