CiaraDenise CiaraDenise

17-06-2016
Geography

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Until the early _______ there were only negligible amounts of free oxygen in the atmosphere.

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taskmasters taskmasters

24-06-2016

During the early earth, when photosynthesis has not yet evolved, there were only negligible amounts of free oxygen in the atmosphere. It was said that the Earth's atmosphere had no free oxygen then. This is about 3.5 billion years ago.

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