U.S. home resales tumbled to a six-month low in November after two straight months of strong increases, underscoring the uneven nature of the housing market recovery. The National Association of Realtors said on Monday existing home sales dropped 6.1 percent to an annual rate of 4.93 million units, the lowest level since May. October's sales pace was revised slightly down to 5.25 million units from 5.26 million units.