An adult human has about 4--6 litres of blood circulating in the body. Blood consists of several types of cells including White Blood Corpuscles or WBC and Red Blood Corpuscles or RBC floating around in fluid called plasma. There are certain protein molecules called antigens located on the surface of the red blood cells and antibodies which are in the blood plasma. The differences in human blood are due to the presence or absence of these antigens and antibodies./nThis videos explains about Blood Grouping Experiment (Amrita University)/nIndividuals have different types and combinations of these molecules. According to the ABO blood grouping system discovered by Karl Landsteiner, there are four types of blood groups.