According to Current Science, Why Didn't Oxygen Begin to Accumulate

question 10

Multiple Choice

According to current science, why didn't oxygen begin to accumulate in the atmosphere for more than a billion years after life appeared on the Earth?

• A) Oxygen was removed from the atmosphere by chemical reactions with surface rocks as quickly as it was released by life.
• B) Early forms of animal life consumed the oxygen released by plants during the first billion years of life on Earth.
• C) Early life did not release oxygen, and oxygen releasing organisms didn't evolve for a billion years after the earliest life.
• D) Oxygen was removed from the atmosphere by dissolving in the ocean as quickly as it was released by life.

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