Think about it. You can plant a seed in a small pot, and grow a plant that takes up more volume than the pot does, and still have a pot full of soil. So, the plant, or at least the vast majority of it, is not comprised of substances from the soil. The only other two things that are added are air and water. So is a plant made up 95% of hydrogen, oxygen, and nitrogen? Where does it get carbon from? Carbon dioxide?
