David Stiglitz, age 17, of Cumberland, Md., for his question:

WHAT WAS NOK?

Nok was a West African civilization that flourished from about 500 B.C. until at least A.D. 200. It was centered in the valley where the Niger and Benue rivers meet. Today, Nok is the name of the village in Nigeria, about 100 miles northeast of Baro.

The people of ancient Nok produced the oldest sculptures found so far in black Africa. These sculptures of animal and human figures were identified by the British archaeologist Bernard Fagg, who named them after the village of Nok. Similar sculptures have been discovered in many other sites in the river valley.

The Nok sculptures are made of terra cotta, a kind of earthenware. They vary in size from one inch high to life size. All the humans heads have pierced ears and the eyes are hollowed out. Scholars do not know what function these sculptures had in the Nok society.

The people of Nok probably farmed the land, but they also hunted and gathered food.

Little is known about the end of the Nok culture.