Consider the following statements (A-C) each with one or two blanks:

A. A dark reddish-brown scum is a clot or coagulum formed mainly of a network of threads called ___(i)____ in which dead and damaged formed elements of blood are trapped.

B. Fibrins are formed by the conversion of inactive _____(ii)______ in the plasma by the enzyme ______(iii)_____.

C. An injury or a trauma stimulates the ____(iv)______ in the blood to release certain factors which activate the mechanism of coagulation.

(i)                     (ii)                        (iii)                      (iv)

 fibrins              fibrinogens           thrombin               platelets

The correct answer is Option (2) -

 (i)                     (ii)                        (iii)                      (iv)

 fibrins              fibrinogens           thrombin               platelets

Blood exhibits coagulation or clotting in response to an injury or trauma. This is a mechanism to prevent excessive loss of blood from the body. A dark reddish-brown scum formed at the site of a cut or an injury over a period of time. It is a clot or coagulum formed mainly of a network of threads called fibrins in which dead and damaged formed elements of blood are trapped. Fibrins are formed by the conversion of inactive fibrinogens in the plasma by the enzyme thrombin. Thrombins, in turn are formed from another inactive substance present in the plasma called prothrombin. An enzyme complex, thrombokinase, is required for the above reaction. This complex is formed by a series of linked enzymic reactions (cascade process) involving a number of factors present in the plasma in an inactive state. An injury or a trauma stimulates the platelets in the blood to release certain factors which activate the mechanism of coagulation.