Answer:
Stage 1 (3.85–2.45 Ga): Practically no O2 in the atmosphere. ... Stage 2 (2.45–1.85 Ga): O2 produced, rising to values of 0.02 and 0.04 atm, but absorbed in oceans and seabed rock. Stage 3 (1.85–0.85 Ga): O2 starts to gas out of the oceans, but is absorbed by land surfaces. No significant change in oxygen level.
Explanation:
Sorry if it is confusing, but that is how my Biology teacher described it to me, if you don't understand, welp, neither do I, LOL.
