Greg Young, Jr., age 10, of Nogales, Ariz., for his question:

ARE THERE MANY KINDS OF LIZARDS?

A lizard is a reptile that is closely related to the snake. Scientists have identified almost 3,000 different kinds of lizards. They come in a wide variety of colors, sizes and shapes.

Lizards lack the built in body temperature control of many other animals. So most lizards live in places where the ground never freezes. Those that live in areas with cold winters must hibernate underground.

Lizards thrive in the tropics and warm parts of the temperate zones. They are the most common reptiles found in deserts and other dry regions. When the desert becomes too hot for comfort, lizards lie in the shade or under the sand to escape the fierce rays of the sun.

Most lizards lay eggs, but some give birth to living young after the eggs hatch inside the female lizard's body.