Name the enzyme produced by the injured cells and platelets, that triggers off the process of clotting:

Q. Platelets are the type of blood cells that participate in the clotting of blood .

Q. Read the statements given below and choose the correct sequence of events leading the formation of a blood clot.
(i) Calcium activates an enzyme.
(ii) Fibrin binds platelets to form a 'plug'.
(iii) Thrombin converts fibrinogen to fibrin.
(iv) Platelets and damaged cells release an activator.

Q. Which of the following is / are wrong about blood clotting?
A. Fibrinogen $\stackrel{Thromboplastin}{\to }Thrombin$
B. Injured tissue + blood Platelets $\to$ Release thromboplastin
C. Prothrombin $\stackrel{Thrombin}{\to }$ fibrin
D. Fibrin + Red Blood corpuscles $\to$ Blood clot

Q. Assertion :The process of clotting can occur in absence of all cellular elements except platelets Reason: Activated platelets release vitamin K