Oil prices fell further below the key $50 threshold Friday , as investors took profits from the recent rally and the dollar strengthened. Trading volume was among the lowest for any day since Christmas, with Monday’s U.S. Memorial Day holiday limiting activity. Many traders simply wanted to get out of the market to limit their risk of exposure to any big or unforeseen changes, helping prices to fall slightly as bullish speculators who drove the rally sold to close their positions, brokers said. “This is just dead,” said Peter Donovan, broker for Liquidity Energy in New York. “We’re not seeing a lot of aggressive activity right before the weekend, which is to be expected.” U.S. crude oil for July delivery settled down 15 cents, or 0.3%, at $49.33 a barrel on the New York Mercantile Exchange. For the week, it gained 92 cents, or 1.9%, marking its third-straight winning […]