All together, the earth's green plants produce an estimated 150 billion to 400 billion tons of
sugar every year - far more material than the combined ouput of all mankind's iron, steel,
automobile, and aerospace factories.  They do this by using the energy from the sun to remove
hydrogen atoms from water molecules and then attach those hydrogen atoms to carbon dioxide
molecules from the air, turning the carbon dioxide into a carbohydrate known as sugar.  This
remorkable process is called photosynthesis.  The plants can then use their new sugar
molecules for energy or can combine them together into starch for food storage or into
cellulose, the tough, stringy material that makes up plant fiber.

                                                                                         (g97 1/22 pp.18-22)