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

$A$ person with $AB$ blood group is called a universal recipient because .....

Blood group $O$ has:

Plasma is a straw-coloured,viscous fluid constituting nearly $A$ $\%$ of the blood,$B$ $\%$ of the plasma is water,and proteins constitute $C$ $\%$ of it. Choose the correct option for the blanks $A, B$,and $C$.

What are Formed Elements?

Write a short note on $ABO$ blood grouping.