Wheat is surging on signs that demand is improving from other countries and businesses that add the grain to products, among other uses. Wheat finished up 3.3 percent Thursday. Corn and soybeans also rose. Sales of wheat to businesses have been solid. And the Agriculture Department says Spain, Iran and the Philippines are among countries that purchased wheat last week. The growing interest in U.S. wheat comes as questions linger about supplies. Global stockpiles are ample but may have been eroded by winter damage to crops in Europe. There also is speculation that farmers may plant other crops this spring in hopes of earning higher profits. In other trading, prices for gold, silver, industrial metals and sugar are higher. Oil, gasoline futures and natural gas are lower.