Answer :
Jonas Salk. Jonas Edward Salk October 28, 1914 – June 23, 1995 was an American medical researcher and virologist. He discovered and developed one of the first successful polio vaccines. He discovered it in Pittsburgh
Jonas Salk. Jonas Edward Salk October 28, 1914 – June 23, 1995 was an American medical researcher and virologist. He discovered and developed one of the first successful polio vaccines. He discovered it in Pittsburgh