Marianne Fay, age 11, of Duluth, Georgia for her question:

Is a sponge a plant or an animal?

Nowadays, most of our squeezy sponges are made of porous plastic. And plastic, of course, is neither plant nor animal. A genuine sponge may look like a plant but actually it is the skeletal remains of a once living animal. It lived and grew in a warm, shallow sea, where it squatted on the bottom, looking for all the world like a bushy little shrub. While it lived, its spongy skeleton was buried within thick layers of fleshy tissue.

A sponge is classed as a pore bearing animal because his whole body is riddled with pores, tunnels and channels. As streams of water flow

through his pores, the fleshy tissues that cover his spongy skeleton extract oxygen and scraps of floating food. A parent sponge may multiply by producing eggs. Or it may sprout baby buds that break loose and go off on their own. And, if a living sponge is cut into sections, even the small scraps can regrow complete new sponge animals.