Mandy Arno, age 14, of Billings, Mont., for her question:

HOW LONG IS THE YANGTZE RIVER?

The Yangtze River, Chinas most important river, is the third longest river in the world. It rises 16,000 feet above sea level in the Kunlun Mountains of Tibet, follows an irregular course east through central China and enters the Yellow Sea 3,434 miles from its source.

The Yangtze River and its branches drain more than 700,000 square  miles of land.

The high mountains, where the Yangtze begins, cause the river to flow rapidly for most of its length. The great gorges of its upper parts make it one of the most beautiful rivers in the world.

Just above I chlang is perhaps the largest potential hydroelectric site in the world. In places, mountains rising more than a mile form the rivers banks.

About half of Chinas ocean trade is distributed over the Yangtze and its branches. Ocean steamers reach Hankow, 680 miles by river from the coast. Smaller boats can go 1,000 miles farther inland.

Thousands of Chinese live on the Yangtze on sailing craft called junks.

Among the great cities along the Yangtze River are Shanghai, Nanking, An ch'ing, I chlang. Chungking and the twin cities of Hankow and Wu chlang.