State which of the following statements are True.

(i) The process of coagulation starts with the release of a substance from RBCs.

(ii) Blood fails to clot readily in the case of deficiency of calcium.

(iii) The solid fibrin and thrombin are one and the same thing.

(iv) The clear liquid that oozes out after the formation of a clot is serum.

(i) False.

Explanation: Process of coagulation starts with the release of a substance from platelets known as thrombokinase or thromboplastin.

(ii) True.

Explanation: Blood fails to clot readily in the case of deficiency of calcium because without calcium thrombokinase will not be able to convert inactive prothrombin to active thrombin which is the major component for the production of the clot.

(iii) False.

Explanation: The solid fibrin and thrombin is not the same thing. Thrombin in presence of calcium ions converts soluble fibrinogen into solid insoluble threads like structures of fibrin in the plasma.

(iv) True.

Explanation: During clot formation, the blood cells get trapped in the network of fibrin which shrinks and squeezes out the rest of the plasma in form of a clear liquid called serum.