Question: Who figured out a way to determine the type of blood?
Disambiguated questions and answers: question: Who figured out a way to determine the ABO type of blood?
Who figured out a way to determine the rhesus factor type of blood?
answer: Karl Landsteiner
Landsteiner
Karl Landsteiner
Karl Landsteiner and Alexander S. Wiener
Alexander S. Wiener
Natural Questions answer: Karl Landsteiner (from the Wikipedia article "ABO blood group system")