Most circulating clotting proteins are synthesized by the:

A. heart
B. liver
C. kidneys
D. bone marrow

b
Rationale: The liver synthesizes most of the circulating clotting proteins. Prothrombin activator (prothrombinase) converts the clotting factor called prothrombin into the enzyme called thrombin. Thrombin then converts fibrinogen to fibrin. This pro-cess normally takes about 6 minutes.