Margaret Williams, age 13, of Atlanta, Ga., for her question:

WHY DOES A SNAKE STICK OUT HIS TONGUE?

Snakes have forked tongues that are long and slender. Every few seconds the tongue appears at the mouth's opening and after darting around for a few seconds, it returns to the mouth. Several seconds later the entire operation is again repeated.

Did you think that the snake can sting with his tongue? Many people believe this, but such is not the case. The tongue is actually harmless. The flicking movement is made as part of the snake's organ of touch. The tongue is also used to pick up particles and to put them into tiny cavities in the roof of the mouth that are linked with the snake's sense of smell. By picking up the particles, the tongue helps the snake to smell.