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
photosynthesi.   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)