Question

What is the most important gas for the origin of life?
A. Carbon
B. Oxygen
C. Water
D. Nitrogen

Answer 1

HintThe theory of the origin of life or the theory of chemical evolution was given by Oparin-Haldane hypothesis. The experimental evidence of their theory was given by S.L. Miller in a laboratory setup.

Complete answer:In the beginning earth atmosphere was reducing with little or no oxygen. However, the atmosphere was rich in water vapors, carbon monoxide, carbon dioxide, nitrogen, and hydrogen gases. The energy required to form simple inorganic molecules and compounds like ammonia, methane, and cyanides was provided by the high temperature, UV light, and lightning and thunder. The superheated steam was present at the earth from the beginning and it would condense with lowering temperatures of the earth and neutralize ammonia, methane, and cyanides into simple organic compounds. The formation of simple gases in the atmosphere was only possible due to the absence of water. This is because the absence of water helped to form the organic compounds. Their reactions with water led to the formation of the first forms of life. Therefore, this makes oxygen the most important element for the origin of life because its presence in the present-day oxidizing atmosphere does not allow the origin of life as it occurred in a primitive reducing atmosphere.
Thus, based on the above information we can conclude that oxygen is the most important gas for the origin of life.
Hence, the correct answer is option (B).

Note:S.L. Miller was an American scientist who proved the Oparin-Haldane hypothesis. Miller sealed gases like water, ammonia, methane, and hydrogen in a spark chamber. He then passed an electric spark through them. The control apparatus was devoid of any other type of energy source. After eighteen days a significant amount of simple organic compounds had formed which proved the theory of chemical evolution.