Oil prices lingered below $72 a barrel Tuesday in Asia as investors remained uncertain about the strength of global economic growth and demand for crude. Benchmark crude for March delivery was down 16 cents at $71.73 a barrel at midday Singapore time in electronic trading on the New York Mercantile Exchange. The contract gained 70 cents to settle at $71.89 on Monday. Investors are staying cautious as swelling debt levels in Europe, high unemployment in the U.S. and fears of Chinese monetary tightening continue to cast doubt over the global economic recovery.