Antigens are present

Assertion: The regulation of $RBC$ production is accomplished by $FSH$.
Reason: Erythropoietin hormone circulates to red bone marrow where it increases stem cell mitosis and speeds up the development of $RBCs$.

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

$A$ person with type $A$ blood group may safely receive a transfusion of

The probability of having a child with blood group $O$ to parents with blood groups $A$ and $B$ is

Biological marriage of one of the following should be avoided: