Which of the following parts of the body is called the heart’s pacemaker?

The sinoatrial node (SA node) is a collection of myocytes that are active pacemakers. The SA node is referred to as the “natural pacemaker” of the heart. It regulates the rhythmic contraction of the heart.
The SA node can produce 70–75 action potentials each minute, which initiates the contraction in the heart muscles.