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 ${\mathrm{Rh}}^{+\mathrm{ve}}$

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

1. Epinephrine

2. Thrombokinase

3. Thrombin

4. Renin

Incomplete double circulation occurs in

1. Fishes

2. Amphibians

3. Reptiles

4. Both 2 & 3

Open circulatory system is present in

1. Arthropods

2. Molluscs

3. Annelids

4. Both 1 & 2

Erythroblastosis foetalis occurs when a factor from mother passes into the foetus through the placenta. The factor is 

1. Rh antigen

2. Rh antibodies

3. Agglutinins

4. ABO antibodies

Oxygen carrier in human blood is 

1.  Carbonic anhydrase

2.  Haemoglobin

3.  Haemocyanin

4.  Both (1) & (3) 

The life span of the erythrocytes in humans is about

1.  120 days

2.  150 days

3.  190 days

4.  180 days

_________ is known as the graveyard of RBCs.

1.  Liver

2.  Spleen

3.  Pancreas

4.  Bone marrow 

Rate of heartbeat is determined by 

1.  Purkinje fibers

2.  Papillary muscles

3.  AV-nodes

4.  SA-node