As someone who loaths chemistry, I have to say photosynthesis is well worth putting some effort in to understand. It is a remarkably elegant series of interactions that makes almost all life on Earth possible. It’s the sort of thing that used to make me think there had to be a god, and that now convinces me that, as Sagan used to argue, the real truth once understood is far more beautiful and moving than the fairy-tale explanations the religious settle for. Basically, energy from light is captured in a chemical bond and then used, in a series of steps, to rearrange atoms to produce food for the plant and, incidentally, the oxygen all animal life requires. And, as a bonus, it uses up the carbon dioxide animals give off as a waste product of cellular respiration, the other side of the ecological see-saw from photosynthesis. Wehn you look into the details, you find such cool things. The chloroplasts in a plant, for example, use exactly the same proton pumping mechanism in their work and the mitochondria in animals use. Evolution makes such wonderful and, dare I say creative, use of what’s lying around to create things entirely new.