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AutoBahned
Join Date: Jul 2007
Location: Greater Metropolitan Nimrod, Orygun
Posts: 55,993
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IIRC, the collision was pre- O2 Earth.
O2 was produced as a waste product by "blue-green algae" - a significant metabolic innovation that killed off almost everything else on the planet (except for tetanus and a few other anaerobes). It was the greatest extinction in Earth history, but usually not counted as little is known that far back.
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