Rose Marie Sir, age 10, of Parma, Ohio,

Why are plants green?

The pine tree wears a furry winter cloak of darkest green. The willow wears drooping leaves of grey‑green and the desert cactus has a thick coat of yellow‑green. The grass changes its shades of green with the seasons. Throughout the plant world, green is certainly the most fashionable color. It is fascinating to study and admire all the different tints and tones of green. But there is a reason for all this greenery. In fact, we could not live in a world without it. there would be no oxygen for us to breathe and no food for us to eat.

Then green color which paints the plant world with various tones and tints is a magic fluid called chlorophyll. It fills the hollow cells of all green plants and its color shines through the fragile cell walls. Basically, chlorophyll is a clear liquid, just as the basic fluid of your blood is a clear liquid. Your blood fluid teems with countless little red bodies called corpuscles. The basic fluid of chlorophyll teems with little green bodies called chloroplasts ‑ and there is only a slight difference between a red blood cell end a chloroplast.

This slight chemical variation, however, makes all the difference between the plant and the animal worlds. Those magic chteroplasts can use sunlight to make plant sugar from air and water. Red blooded animal cannot do this. A plant takes the simple sugar made by its chloroplasts and uses complex processes to turn it into various fats, proteins and carbohydrates, These are the foods, of course, that red blooded creatures must eat. The rabbit eats the grass and the fox eats the rabbit.

There may be a billion chloroplasts near the surface of a summer leaf. During the sunny

During the sunny hours they are all busy with photosynthesis, their magic recipe which means putting together with light. We do not know exactly how it works, but we know the ingredients. Each recipe calls for six molecules of carbon dioxide from the air and six molecules of water from the soil. The energy from light is used to break these molecules apart into atoms and to reassemble these atoms to make a molecule of simple plant sugar. In the rearrangement, six molecules of oxygen are left over and returned to the air. The recipe is repeated billions of times during every daylight hour. The waste oxygen from photosynthesis is wafted around the world and it supplies all living things with breathable air.

The sugar made by the green chloroplasts feeds the plants. The plants feed the animals who also feed each other. Without green chlorophyll, the world would run out of oxygen in a few days and out of food in a few weeks. And chlorophyll is the magic fluid which paints the plant world green,