Their count is about $2-3$ percent of the total white blood cell count in the blood.

Which substance does the clot formed in coagulation consist of?

Properties of leucocytes are:
$I$. They are nucleated.
$II$. They are denucleated like $RBC$.
$III$. They are $6000-8000 \; mm^{-3}$ of blood.
$IV$. They are long-lived.
$V$. They are short-lived.
Choose the appropriate option with correct properties.

One of the factors required for the maturation of erythrocytes is

Match the following columns:

Column-$I$ (Blood Group)	Column-$II$ (Antibodies)
$P$. $A$	$I$. Absent
$Q$. $B$	$II$. $a$ (anti-$B$)
$R$. $AB$	$III$. $b$ (anti-$A$)
$S$. $O$	$IV$. $a, b$ (anti-$A$ and anti-$B$)

Which are the most active white blood cells?