[Campbell Biology P.583] What was the primary fate of the free O2 produced by early oxygenic... | Practice Question

What was the primary fate of the free O2 produced by early oxygenic photosynthesis before it began to accumulate significantly in the Earth's atmosphere?

  • A: It immediately diffused into the atmosphere, leading to the "Oxygen Revolution."
  • B: It reacted with atmospheric carbon dioxide to form new organic molecules.
  • C: It dissolved in the surrounding water and reacted with dissolved elements like iron.
  • D: It was immediately consumed by anaerobic prokaryotes, limiting its accumulation.

Explanation

The text states: "the free O2 it produced probably dissolved in the surrounding water until it reached a high enough concentration to react with elements dissolved in water, including iron. This would have caused the iron to precipitate as iron oxide..."