Roger Best, age 13, of Kalispell, Mont., for his question:

HOW LARGE IS THE GOBI DESERT?

The Gobi is a vast desert area of Central Asia that is principally located in Mongolia. It measures about 1,000 miles from east to west and about 600 miles from north to south. Sometimes it is called the Chinese Shamo, or "sand desert."

The general form of the Gobi is that of a plateau between higher mountains. The height of the plateau ranges from 3,000 feet above sea level in the east to 5,000 feet in the west. the surface of the Gobi plateau consists in the main of rolling gravel plains.

The southeast portion of the Gobi is completely waterless. The remainder of the region, approximately three quarters of the area, has a thin growth of grass, scrub and thorn sufficient to feed the flocks of the nomadic herders who live there. Water is available in wells and occasional shallow lakes.

The first Europeans to traverse the Gobi were the Italian traveler Marco Polo and his father and uncle, who crossed the region about 1275. The next recorded crossing is that of the French Jesuit priest Jean Francois Gerbillon in the 1680s.