Question

the cardiac electrical impulse normally begins spontaneously in the sa node because
multiple choice
of the superior location of the sa node in the right atrium.
this area produces action potentials more rapidly than any other portion of the conduction system.
of action potentials from the cardioregulatory center.
of the rich sympathetic innervation of the sa node.
the sa node is the only area of the heart capable of spontaneous depolarization.

Explanation:

The sino - atrial (SA) node is the natural pacemaker of the heart. It initiates the cardiac electrical impulse spontaneously because it has the fastest rate of spontaneous depolarization compared to other parts of the cardiac conduction system.

Answer:

this area produces action potentials more rapidly than any other portion of the conduction system.