Bob Caserta, age 13, of Birmingham, Ala., for his question:

WHERE IS THE GREAT BARRIER REEF?

The Great Barrier Reef is the largest coral formation in the world. It extends for about 1,250 miles in a broken chain of reefs along the northeast cost of Australia.

The coral ridge rises out of the sea some distance from the shore and follows the coastline of Queensland, the second largst state in Australia.

Part of the Great Barrier Reef lies only 10 miles from the shore, while other parts of it are as far as 150 miles from the coast.

Since the mid 1960s, large numbers of crown of thorn starfish have been feeding on the living coral of the reef. This feeding has destroyed large areas of what would have become new reef. Without regular growth, the reef faces the danger of gradually disappearing as th8 old reef wears away.

Coral is a limestone formation formed in the sea by millions of tiny animals. The living coral forming animals color the formation in beautiful shades of tan, orange, yellow, purple and green. When the animals die, they leave limestone "skeletons" that form the foundations of barriers and ridges.