What is the difference between the function of platelets, white blood cells and red blood cells?

They are all components of blood. Platelets are small fragments of cells and help blood to form clots. This stops the body from bleeding when a blood vessel gets damaged. White blood cells destroy microorganisms, which cause diseases. Therefore, by destroying microorganisms, white blood cells prevent illnesses or help the body recover from them. Red blood cells carry oxygen and transport it around the body. Oxygen is used by the body in respiration, which creates energy.