This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cardiovascular system, Subject name: Physiology
Which of the following coagulation factors causes cross-linking and stabilization of clot? 
Select and explain. 
A. Factor XIII, B. Thrombin, C. Factor VIII, D. Factor IX
A: Factor XIII
Answer: A: Factor XIII 
Explanation: The loose aggregation of platelets in the temporary plug is bound together and conveed into definitive clot bg fibrin. Fibrin is initially a loose mesh of interlacing strands. It is conveed by the formation of covalent cross-linkages to a dense tight aggregate. The latter reaction is catalyzed by activated factor 13 and requires calcium. Ref: Ganong&;s Review of medical physiology, 24th edition.Pg no. 566