34. Prothrombin which helps in clotting of blood is released by A.lymphocytes B.erythrocytes C.monocytes D.blood platelets
Answer: Option D Solution: Prothrombin is a plasma protein which is converted into thrombin in the presence of thromboplastin released by platelets at the site of injury. The thrombin then converts protein fibrinogen into insoluble fibrin and thus aids in blood clotting.
