Which of the following substances, if introduced into the bloodstream, would cause coagulation of blood at the site of its introduction?

1. Thromboplastin

2. Fibrinogen

3. Heparin

4. Prothrombin 

Vitamin which induces maturation of R.B.C.:
1. $B_1$
2. A
3. $B_{12}$
4. D

Arterial blood pressure in human beings is:
1.  120 and 80 mm Hg
2.  150 and 100 mm Hg
3.  50 and 100 mm Hg
4.  None of the above

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