NEW YORK (Reuters) - Wall Street stocks fell sharply in volatile trading on Friday, with the Nasdaq confirming it is in a bear market, as concerns of slowing economic growth led investors to flee stocks in high-valuation sectors such as technology and communication services. The closing numbers are displayed after the closing bell of the New York Stock Exchange (NYSE) in New York, U.S., December 21, 2018. REUTERS/Bryan R Smith. The major U.S.