31. The release of oxygen in photosynthesis is derived from what input material?
Water, (H2O). Remember a total of 12 molecules of water are required to run photosynthesis. Six waters to make the sugar glucose (12 hydrogens) and the oxygen left over combines to form the gas O2. The other six waters are used to generate (18) ATPs and those hydrogens and oxygen left over, later recombine to again form water.