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Geography, 13.01.2020 09:31 babbybronx

When did cyanobacteria start producing pure oxygen?

a. after the hadean eon
b. after the proterozoic eon
c. during the hadean eon
d. during the phanerozoic eon

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When did cyanobacteria start producing pure oxygen?

a. after the hadean eon
b. a...
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