This is not correct: "Food is created by taking CO2, keeping the C and releasing the O2." The resulting O2 actually comes from a pair of H2O. Consider the rea

This is not correct: "Food is created by taking CO2, keeping the C and releasing the O2." The resulting O2 actually comes from a pair of H2O. Consider the reaction performed by purple sulfur bacteria, which are related by evolution but have a slightly different reaction. It is this: CO2 + 2 H2S gives [CH2O] + H2O + 2 S There, carbon dioxide reacts with hydrogen sulfide to give water, sulfur, and part of a carbohydrate. Photosynthesis in plants is the same sort of reaction, but the situation is less obvious because there is H2O on both sides of the reaction. We've proven what happens by experiments with radioisotopes. The entire photosynthesis reaction consumes 6 CO2 and 12 H2O to produce 6 H2O, 6 O2, and a sugar. From the 12 H2O, half of the H goes to the sugar and the other half goes to producing new H2O. From the 12 H2O, all of the O goes to producing O2. From the 6 CO2, half of the O goes to the sugar and the other half goes to producing new H2O. From the 6 CO2, all of the C goes to producing sugar.