Where are the non-nucleated blood cells produced?

During the process of blood clotting,fibrin is formed by:

The $pH$ of human blood varies between

Which of the following is an agranulocyte?

Which substance is secreted by eosinophils during an allergic reaction?

Given below are two statements:
Statement $I$:
The coagulum is formed of a network of threads called thrombins.
Statement $II$:
Spleen is the graveyard of erythrocytes.
In the light of the above statements,choose the most appropriate answer from the options given below: