Colleen McMullen, age 11, of Toronto, Ont., Canada, for her question:

WHAT DOES A TREE FROG LOOK LIKE?

He has a froggy face and smile and the usual big, bulging eyes on top of his head. Unless you look closely, you might mistake him for an ordinary frog. However, you are most likely to find him among the trees and bushes. What's more, he has extra large fingers and toes, tipped with round disks that can cling to solid surfaces. He uses them to climb among the boughs. Ordinary frogs are expert swimmers and divers  but only the tree frogs can climb trees.

There are dozens of different tree frogs, ranging in size from half an inch to more than five inches. Most of them are smaller than other frogs, and most have high, peeping voices. As a rule, their skins are colored to match their surroundings. And some types can change colors through pasty white, gray and brown and sometimes green.