Respuesta :
Karl Landsteiner understood the different blood groups A, B, AB, and O. He was a biologist and physician that distinguished these main blood groups in the 1900. He was also the man behind the discovery of polio virus in 1909 and had received the Nobel Prize in Physiology in the year 1930. Today he is currently recognized as the father of transfusion medicine.
Answer:
d) understanding A, B, AB, and O blood groups
Explanation:
its says so e 2020