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MCAT Organic Question — Abiogenesis Theory

According to the abiogenesis theory of the origin of life, the primitive atmosphere consisted primarily of:


A) CH4, H2O, O3

B) NH3, O2, H2

C) NH3, CH4, H2

D) O2, CH4, H2O



The abiogenesis theory posits that early in Earth’s history, the atmosphere was made up of a “primordial soup” of gases that created a highly reducing environment. Oxygen and ozone were not present, as they would have oxidized any biological macromolecules. Thus, choices (A), (B), and (D) are wrong.

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