In human body, “Thrombin” plays important role in which of the following physiological processes?
[A] Excretion
[B] Blood clotting
[C] Reproduction
[D] Growth

Blood clotting
Thrombin is a serine protease that in humans is encoded by the F2 gene. In the blood coagulation pathway, thrombin acts to convert factor XI to XIa, VIII to VIIIa, V to Va, and fibrinogen to fibrin.