mention advantages of blood as a circulatory fluid over water s a circulatory fluid.

Blood is more viscous than water.  This is important for maintaining a constant flow through the blood vessels.

Blood carries the cells which carry out unique important functions. The RBCs carry the respiratory pigment which help in transport of respiratory gases, WBCs are important in defense mechanism of the body and platelets are important in blood clooting. Cells are not present in water.

The plasma of blood contains several important proteins, all of which are absent in water.