Energy and crop prices tumbled Monday as the dollar reversed course from its weakness, driving commodities broadly lower amid fear that the currency would see more gains. Crude oil fell more than 2%. Corn tumbled 5%, leading losses in agricultural markets, including wheat and corn. The Reuters-Jefferies CRB index, a commodities basket that tracks 19 mostly U.S.-traded futures markets, was down more than 1% as other markets like copper, gold, cocoa