(If there are no antigens at all on the surface of the red blood cells, all three possible antibodies are present in the blood plasma: A, B and Rh antibodies.). The blood type notation O Rh-indicates which antigens and antibodies are present in the blood.
There were 2,473 billionaires in the world, as of Wealth-Xâs last count through 2015. That was a 6.4 percent increase in billionaires from the year before. But who these billionaires are and what theyâre like is more difficult to discern.
Image caption Bill Gates has been named the world's richest person for 16 of the last 20 years. Bill Gates has been declared the richest man in the world for the 16th time by Forbes magazine's annual ranking of global billionaires. The Microsoft founder once again beat Mexican businessman Carlos Slim to the top spot. Mr Gates' net worth rose by just over $3bn (Â£1.94bn) in the year to 13 February, to $79bn. There are a record 1,826 billionaires in the world, Forbes said, an increase of 181 in the past 12 months.