Douglas Bone, age 11, of Florence, S.C., for his question:

WHAT IS CHLOROPHYLL?

The green material in plants is called chlorophyll. Plants cannot make food without it, and since animals lack chlorophyll they depend on green plants for food.

This basic process is necessary for all food production for living things: chlorophyll, using energy from light, changes carbon diode and water into sugar and oxygen.

In the fall, when sunlight is not sufficient, the cholorophyll fades out of the leaves of many trees and shrubs, permitting other colors to show through. As the sun's rays become less direct, and chlorophyll weakens, brown, yellow and red pigments are revealed.