Blood is the fluid tissue which consist red blood cells (Erythrocyets)， white blood cells (Leucocytes) and platates (Thrombocytes) floating in liquid called plasma. The main importance of mammalian blood includes;-
1. Help in the transportation of organic solute from the site of absorption to the storage part and from storage part to different part of the bodyfor using in a different metabolic activities.
2. Help in transportation of metabolic wastes such as urea from the liver (site of production) to the kidney to be removed out.
3. Help in transportation of respiratory gases such as oxygen and carbon dioxide from the lungs to the body tissue and from the body tissue to the lungs respectively.
4. Help in maintenance of body solute potential and pH done by plasma protein of the blood.
5. Help in defence of the body sue to the presence of antibodies and lymphocytes of white blood cell.
f. It participate in the regulation of body heat (thermo regulation) from high heat generation.