Correct option is C
Correct Answer:
Option (c) — Reducing atmosphere with gases such as methane and ammonia
Explanation:
According to the Oparin–Haldane hypothesis (also known as the Primordial Soup Hypothesis), the early Earth’s atmosphere was reducing, meaning it lacked free oxygen.
Instead, it was rich in hydrogen (H₂), methane (CH₄), ammonia (NH₃), and water vapor (H₂O).
This reducing environment favored the formation of simple organic molecules such as amino acids and nucleotides — the building blocks of life — from inorganic precursors through chemical evolution.
Information Booster:
-Proposed independently by A.I. Oparin (1924) and J.B.S. Haldane (1929).
-They suggested that lightning, volcanic heat, and UV radiation provided energy for abiotic synthesis of organic molecules.
-This hypothesis was later supported by the Miller–Urey experiment (1953), which demonstrated that amino acids could form in such a reducing environment.
Additional Knowledge (Incorrect Options Explained):
(a) Incorrect — Early atmosphere was not rich in oxygen; oxygen appeared later through photosynthesis by cyanobacteria.
(b) Incorrect — Carbon dioxide was present, but oxygen was negligible in early Earth’s atmosphere.
(d) Incorrect — The early atmosphere was very different from today’s oxygen-rich environment.
