In 1900, Karl Landsteiner made a groundbreaking discovery: he found that human blood is not the same! π©Έ
By mixing blood from different people in his lab, he noticed some combinations clumped together, while others did not. This led him to identify the four main blood groups: A, B, AB, and O. π©Ή
This was a huge revelation because it meant that people who need blood transfusions need to match their
blood type. His discovery changed how we perform surgeries and treat injured patients, making it safer for everyone!