The chief difference between $RBCs$ of human and frog is:

$A$ person with an unknown blood group under the $ABO$ system has suffered significant blood loss in an accident and requires an immediate blood transfusion. His friend,who has a valid certificate of his own blood type,offers to donate blood without delay. What would be the blood group of the donor friend?

State the percentage of water and proteins in blood plasma.
Water $\quad$ Proteins

Which one of the following plasma proteins is involved in the coagulation of blood?

What is the function of serotonin in the blood?

Antibodies are .......