Jody Martin, age 12, of Austin, Texas, for her question:

WHAT IS THE DIFFERENCE BETWEEN A SWEET POTATO AND A YAM?

A sweet potato is a vegetable of the morning glory family of plants. Its large, fleshy roots are a popular food. Sweet potatoes are often called yams, but yams belong to a completely different family.

Yams are a major food crop in many tropical countries, including western Africa, India, countries of Southeast Asia and the Caribbean Sea. Few yams are grown for food in the United States because the weather is too cold and the growing season is too short.

Sweet potatoes are grown chiefly in the southern U.S.

Sweet potatoes have high energy value and contain vitamins A and C. They may be bought fresh, canned or dehydrated. Sweet potatoes first grew in tropical regions of the Western Hemisphere and were raised in colonial Virginia during the early 1600s.

Here, in order, are the leading sweet potato growing states: North Carolina, Louisiana, Virginia, Mississippi, California, Texas, Georgia, Alabama, Tennessee and Maryland.