What is the effect of the parasympathetic nervous system on the heart rate?

Fall in blood pressure due to loss of blood is soon restored because the

Which of the following factors increase the heart rate?
$(A)$ Sympathetic nerve signals
$(B)$ Parasympathetic nerve signals
$(C)$ Adrenal medullary hormones
$(D)$ Vagus nerve
$(E)$ Thyroxine hormone
$(F)$ Acetylcholine

If the sympathetic nerve to the heart is cut off,the heart beat will

How is the regulation of cardiac activity performed?

Stimulation of the vagus nerve will make the heart beat