Michael Sargent, age 17, of Ottawa, Ontario, Canada, for his question:

TELL ME ABOUT THE YAK.

The yak is a wild ox of Asia. It lives on the high plateaus of Tibet, often more than 16,000 feet above sea level. He stands over six feet tall at the shoulders and may weight up to 1,200 pounds. He has a rather sour disposition. The wild yak is in danger of extinction.

The domesticated yak, often called the grunting ox because of the sound he makes, is the result of many generations of breeding. Smaller and more docile than the wild yak, he is used as a pack animal and may happily carry a heavy load 20 miles a day.

In Tibet, the domesticated yak can carry passengers and mail. The female provides rich milk. The animal's meat is said to be delicious either fresh or dried. The hair is used for making cloth, while the hide is used for saddles, boots and other items of clothing.