<Dl> <Dd> CO + 2H S → CH O + H O + 2S </Dd> </Dl> <Dd> CO + 2H S → CH O + H O + 2S </Dd> <P> Few modern organisms use this method of photosynthesis, making their water contribution negligible . But on the hydrogen - sulfide - rich and oxygen - poor early Earth, a small but significant portion of Earth's water may have been synthesized biochemically through this pathway . </P>

How did condensation of water vapour formed oceans