Heather Gill, age 12, of St. Catharine,, Ont., for her question:

How high are the Rocky Mountains?

The great Rocky Mountains have been called the backbone of North America. They stretch like a spiny from New Mexico up through the Western States, through British Columbia and the Canadian Yukon. In this vast uplifted system there are high peaks, low peals, valleys and wide plateaus where no peaks are in sight.

The highest single peaks are in the Canadian Yukon. Mount Logan, the highest Rocky Mountain peak, towers 19,850 feet above sea level. Mount St. Elias is 18,008 feet high.

The bulkiest hump of the Rockies is in Colorado and Utah. Here the great mountain system is 300 miles wide. Colorado has 46 peaks higher than 11,000 feet and more than 250 between 13, 000 and 14,000 feet. In Colorado is Rocky Mountain National Park with its crown of white capped peaks. Also in Colorado is Mt. Elbert, 14,431 feet high and the highest Rocky Mountain peak in the United States.