Biological compounds such as carbohydrates, fats, and proteins
are thermodynamically unstable in the presence of O2, since, upon
combustion, they will undergo exothermic reactions with O2 to form
CO2, H2O and other simple and stable compounds. On the other hand,
aerobic life forms require O2 for generating energy, via oxidation
reactions (respiration), needed for myriad metabolic activities.
Explain how the special electronic structure of O2 allowed aerobic
life on the planet to evolve in the presence of an oxidizing
atmosphere,...