The Associated PressWHEAT GAINS: Wheat prices surged on signs that demand is improving from other countries and businesses that add the grain to products, among other uses. The growing interest comes as questions linger about global stockpiles ahead of the spring planting season. RECOVERING METALS: Copper, platinum and palladium rose after two surveys showed manufacturing in the Northeast expanded in March, which provided more proof of the strengthening U.S. economy. Gold and silver also rose. SUGARY MOVE: Sugar prices jumped 4.3 percent on speculation that Europe may be considering significant imports. The price has risen nearly 10 percent this year.