Jean Clements, age 11, of Staten Island, N.Y. for her question:

WHAT DO TONSILS DO?

Tonsils, those fleshy folds in your throat, form the first line of defense against airborne infections. The tonsils and adjoining lymph tissue trap invading bacteria and destroy them.

Children living in close quarters at home and attending overcrowded schools, scientists have found, tend to have larger tonsils than those living in less crowded conditions. This is probably caused by the additional bacteria that the tonsils are attempting to destroy.

Inflammation of the tonsils is called tonsillitis. Sometimes doctors decide to remove the tonsils.