1. Human blood is composed of Blood cells and plasm. Plasma is the fluid portion of the blood.
2. Blood cells are of three types – Red blood cells, White blood cells and Blood platelets.
3. White blood cells are again of different types.
4. The white blood cells boost our immunity and protect us from the harmful, disease causing micro organisms that enter into our body.
5. They act like police force of our body.
6. Red blood cells have a colouring pigment called Haemoglobin in the RBC, which gives blood the red colour.
7. Haemoglobin acts as a carrier for oxygen and carbon dioxide and plays a key role in respiration.
8. Blood platelets play an important role in coagulation of blood when there are cuts and wounds.
9. Blood plays an important role in the transport of materials in animals.
10. Blood is the medium to carry the digested food materials and the inhaled oxygen to all parts of the body.