Which enzyme is responsible for the conversion of inactive fibrinogens to fibrins?

1. Epinephrine

2. Thrombokinase

3. Thrombin

4. Renin

Persons with 'AB' blood group are called as "Universal recipients". This is due to:

1. Presence of antibodies, anti-A and anti-B, on RBCs.

2. Absence of antibodies, anti-A and anti-B, in plasma.

3. Absence of antigens A and B on the surface of RBCs.

4. Absence of antigens A and B in plasma.

Which of the following conditions causes erythroblastosis fetalis?

1. Mother ${\mathrm{Rh}}^{+\mathrm{ve}}$ and fetus ${\mathrm{Rh}}^{-\mathrm{ve}}$

2. Mother ${\mathrm{Rh}}^{-\mathrm{ve}}$ and fetus ${\mathrm{Rh}}^{+\mathrm{ve}}$

3. Both mother and fetus ${\mathrm{Rh}}^{-\mathrm{ve}}$

4. Both mother and fetus ${\mathrm{Rh}}^{+\mathrm{ve}}$