$Thrombocytes$ are cell fragments rather than true cells.

$A$ human female with blood group $A$ has:

Mature human $RBCs$ are enucleated. Which of the following is the most appropriate explanation for this?
$(i)$ They do not need to reproduce.
$(ii)$ They are somatic cells.
$(iii)$ They do not perform metabolism.
$(iv)$ Their internal space is available for $O_2$ transport.

The erythropoietic organs of a foetus are . . . . . . and . . . . . . .

$A$ person with antigens '$B$' in $RBC$ and antibodies '$a$' (anti-$A$) in the plasma belongs to the blood group

Blood clotting can be prevented in a test tube by adding a little