Mark the pair of substances among the following which is essential for coagulation of blood.

Options

A. Heparin and calcium ions
B. Calcium ions and platelet factors
C. Oxalates and cirtrates
D. Platelet factors and heparin

Answer

C

Explanation

Certain factor released by the tissues at the site of injury initiate coagulation. Calcium ions play a very important role in clotting. Blood clotting can also be prevented in a test tube by adding a little oxalate or citrate. Oxalate or citrate reacts with calcium to form an insoluble compound, so free calcium ion necessary for clotting are not mentioned in the option (c)