The correct statement in respect of protein haemoglobin is that it:

1. Maintains blood sugar level

2. Acts as an oxygen carrier in the blood

3. Forms antibodies and offers resistance to diseases

4. Functions as a catalyst for biological reactions 

The cardiac pacemaker in a patient fails to function normally. The doctors find that an artificial pacemaker is to be grafted into him. It is likely that it will be grafted at the site of:

1. Purkinje system

2. Sinoatrial node

3. Atrioventricular node

4. Atrioventricular bundle 

Lead concentration in blood is considered alarming if it is:

1. 30 µg/100 ml

2. 4-6 µg/100 ml

3. 10 µg/100 ml

4. 20 µg/100 ml 

In the ABO system of blood groups, if both antigens are present but no antibody, the blood group of the individual would be:

1. O

2. AB

3. A

4. B

Ventricular contraction is in command of :
1.  S.A. Node
2.  A.V. Node
3.  Purkinje fibers
4.  Papillary muscles

Which of following occurs in maximum concentration in blood plasma (ECF):
1. $K^{+}$

2. $M{g}^{+2}$

3. $C{a}^{+2}$

4. $N{a}^{+}$

Agglutination occurs in blood present in a test tube. This indicates:
1.  Antibodies are present in plasma
2.  Antigens are present on R.B.C.
3.  Antigens are present in plasma
4.  Antibodies are present on R.B.C

At which point, the pulmonary artery is different from the pulmonary vein:
1. Its lumen is broad
2. Its wall is thick
3. It has valves
4. It does not possess endothelium

The reason why hair loss is more in old age:

1. Reduction of blood supply

2. Decrease in protein synthesis

3. Low energy production

4. Reduced storage of glycogen

Erythroblastosis fetalis is caused when:

1. Rh^– female & Rh⁺ male

2. Rh⁺ female & Rh^– male

3. Rh⁺ female & Rh⁺ male

4. Rh^– female & Rh^– male