Spontaneous contraction is seen in -

Ans. is 'b' i.e., Smooth muscles o Single unit smooth muscles have their own-rhythmic contractility myogenic tone that is independent of the nerve supply.o The rate of contraction may be determined by the pacemaker regions present within the muscles.o The nervous influence only modulates their activity, i.e., the role of the nerves is to increase or decrease the rate of rhythmic contraction.