At the site of an injury, a dark reddish-brown scum is formed that traps dead and damaged formed elements. The most abundant of these trapped elements have an average life span of 120 days and are destroyed in organ 'X'. The threads of this scum are formed from soluble plasma proteins by the action of an enzyme 'Y'. Identify 'X' and 'Y'.

Step-by-step solution

The most abundant formed elements in blood are erythrocytes (RBCs), which have an average life span of 120 days. They are destroyed in the spleen, making 'X' the spleen. The dark reddish-brown scum is the coagulum or clot, which is formed mainly of a network of threads called fibrins. These fibrins are formed by the conversion of inactive fibrinogens in the plasma by the enzyme thrombin, making 'Y' thrombin. Fibrin is the structural thread itself, not the enzyme. Thrombokinase is the enzyme complex that activates p