Just about every substance you pull out of a plant or animal is made of mostly carbon atoms—except water, of course. In time, organic chemists learned how to turn plant and animal compounds into all kinds of other things. Chemists used plant and animal compounds to make new compounds that are not found in nature. Even though these substances weren’t natural, they had something in common with plant and animal matter: their molecules were still made of carbon atoms. After all, when chemists turn one substance into another, all they are doing is taking apart its molecules and putting the atoms back together in different ways. Carbon in, carbon out.