Write the features that distinguish between the two

a. Plasma is a liquid form of blood which does not have cells and is treated with EDTA like anticoagulant whereas serum is a liquid form of blood after coagulation

b. In an open circulatory system, the blood flows through large vessels into sinuses whereas in the closed circulatory system the blood flows through a closed network of blood vessels.

c. Sino-atrial node is present in the right atrium near the opening of superior vena cava whereas the atria-ventricular node is present in the right atrium near the base of the interatrial septum.