What are the basic components of blood?

Very simply, Red corpuscles - containing haemoglobin to carry oxygen round the body from the lungs and carbon dioxide from the cells back to the lungs. White blood cells - several different types, but the main function is to remove infective bacteria from the blood. Platelets - small parrticles in the blood, necessary for blood clotting e.g. when you cut your finger Plasma - a yellowish watery fluid that is left after the red corpuscles, white cells and platelets are removed, that dissolves various substances (eg sugar, food, minerals, waste products etc) for transport round the body.