i. Blood: It is specialised kind of living fluid connective tissue of opaque red colour of alkaline reaction and salty in taste. Its specific gravity is 1.050-1.060. The blood contains a fluid part of the plasma, and the solid part the corpuscles.
ii. Serum: is the name given to blood plasma which has its protein fibrinogen removed. In this form, the plasma cannot clot, so it can be stored in hospital blood banks for transfusions in emergencies.