Eric Villaverde, age 11, of Staten Island, N.Y., for his question:

HOW MANY KINDS OF SHARKS ARE THERE?

About 250 different species of sharks can be found living in the oceans of the world. Most of them live in warm seas.

While sharks have the reputation of being man eaters, only about 25 species have been known to attack human beings. Less than 100 shark attacks a year are reported throughout the entire world.

All sharks are meat eaters. Most of them live on live fish, including other sharks. Sharks usually eat their prey whole, or they tear off large chunks of flesh. They also feed on dying or dead animals.

Sharks have no bones. Their skeletons are made of a tough, elastic substance called cartilage.