Blood may seem like it’s all the same, just a red liquid. But if you look at a drop of your own blood under a microscope, you would see objects floating in it that look like balls and doughnuts. If ...

There are different blood types: A, B, AB, and O, with each also being Rh-positive or Rh-negative. Knowing your blood type is important for safe blood transfusions and organ transplants. Type ...

O- blood is the universal donor type because it can be used for anyone. AB+ blood can receive any type of blood, making it the universal recipient. Blood types need to match, or the immune system will ...