Stimulation of the vagus nerve will make the heart beat

Innervation of heart in the intact animals is primarily meant for

The pacemaker stimulates:

Heart beats are accelerated by

Heart beat decreases in the following conditions $EXCEPT$ . . . . . . .

$A$: The resting heart rate,about $75$ beats/minute,is usually lower than the autorhythmic rate of the $SA$ node ($90-100$ beats/minute).
$R$: At rest,the parasympathetic nervous system effects dominate the heart rate.