This is because blood is a SUSPENSION. Blood is composed of different type of particles with different densities. Blood is made up of platelets, white blood cells, red blood cells and the plasma. Blood is an heterogeneous mixture, which mean that all the components of the blood can be separated from one another. A suspension is a mixture which separate out when left standing; blood can be described as a suspension.
the particles of solid silver at room temperature are closer together and are colliding with each other more often therefore making it a solid. the particles of liquid water at room temperature are further apart and don't collide as often and have more room to move.