Richard Crumley, age 11, of college park,  Ga., for his question:

What is symbiosis?

This word belongs in the science of biology, for it means living together. The number of plants and animals living together on our planet is past counting, and all of them have some kind of symbiotic relationship with certain other living things. Some of these relationships are one sided, and some are happy partnerships of give and take.

The symbiosis between a mistletoe plant and an oak tree is very one sided. The mistletoe is a parasite that feeds on the sap of the tree while taking more than its share of air and light. It gives its host nothing but trouble for what it takes. A Lichen, however, is an example of give and take symbiosis., it is a union of two plants in which an alga provides ant food and a fungus provides moisture for the partnership.