Donors and recipients in a blood transfusion process can be:

Which of the following cells secrete substances like histamine,serotonin,and heparin?

$A$ person meets with an accident and a great loss of blood has occurred. There is no time to analyze his blood group. It is safe to transfuse blood of group:

Antigens are present

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.

Factors for coagulation or clotting of blood are present in the plasma in an .......... form and plasma without clotting factor is called ........