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

Bundle of His is a network of:

1. Muscle fibres distributed throughout the heart walls

2. Muscle fibres are found only in the ventricle wall

3. Nerve fibres distributed in ventricles

4. Nerve fibres found throughout the heart