Life didn't start out breathing oxygen, oxygen was actually a waste product and the introduction of oxygen into the atmosphere was a disaster for a lot of the l

Life didn't start out breathing oxygen, oxygen was actually a waste product and the introduction of oxygen into the atmosphere was a disaster for a lot of the life existing at that time... https://en.m.wikipedia.org/wiki/Great_Oxygenation_Event https://en.m.wikipedia.org/wiki/Great_Oxygenation_Event