Both $RBCs$ and $WBCs$ are formed in

By using the stain methylene blue,the . . . . . . can be differentiated from other corpuscles.

When red blood corpuscles containing both $A$ and $B$ antigens are mixed with your blood serum,they agglutinate. Hence,your blood group is . . . . . . type.

The nucleus of granular $WBC$ is mainly .....

Match the terms in Column-$I$ with their explanation in Column-$II$:

Column-$I$	Column-$II$
$A$. Polycythemia	$I$. Decrease in number of WBCs
$B$. Erythrocytopenia	$II$. Increase in number of RBCs
$C$. Leukemia	$III$. Decrease in number of RBCs
$D$. Leucopenia	$IV$. Uncontrolled increase in number of WBCs

What is the function of serotonin in the blood?