The clot formed is not stable unless extensive cross-linking occurs. This extensive cross-linking of blood clot is done by:

Ans: D. Factor XIIIConversion of fibrinogen into cross-linked fibrin:Thrombin directly conves soluble fibrinogen into fibrin monomers.Fibrin monomers polymerize into an insoluble clot & also amplifies coagulation process - By activating factor XI, factors V & VIII.Also stabilizes secondary hemostatic plug - By activating factor XIII.Factor XIII - Covalently cross-links fibrin.Ref: Robbing 9/e 11 9