Teddy King, age 12, of Niagara, Ont., for the question:

Does the MacKenzie River have a delta?

The great MacKenzie empties its waters into the chilly Arctic Ocean, many miles north of the Arctic Circle. It is a north flowing river, gathering its waters from the east slopes of the Rockies and from three huge northern lakes. From its source to the Arctic Circle it flows more than 2,500 miles, Only the Missouri‑Mississippi River is longer in North America.

For most of its journey the great river flows through virgin forests and wild scenic beauty. Inside the 1irctic Circle it must cut through half frozen tundra country. Here it breaks into countless streams and branches, These mud‑choked channels form a delta, the flat, tundra delta of the MacKenzie River. Recently large deposits of oil have been found a few hundred miles south of the delta.