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PCAT Chemical Processes – 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. This leaves (C) as the correct answer.

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