chemical reactions do not cause the total number of atoms to change & photosynthesis is a kind of chemical reaction ->  the total number of atoms stay the same in chemical reaction  the total number of atoms stay the same in chemical reaction & photosynthesis is a kind of chemical reaction ->  the total number of atoms stay the same in photosynthesis  the total number of atoms stay the same in photosynthesis & 6 atoms of carbon involves in photosynthesis & carbon is a kind of atom -> the number of carbon atoms stays at 6 in photosynthesis