Which of the following describes a characteristic of a normal sinus rhythm?

A normal sinus rhythm is characterized primarily by a regular rhythm, which means that the intervals between heartbeats are consistent. In a healthy individual, the heart rate is driven by the sinoatrial node, resulting in a predictable pattern of electrical activity and cardiac contraction. This regularity helps ensure efficient blood flow throughout the body.

Heart rates can vary within a normal range, typically from 60 to 100 beats per minute, so the categorization of high or low heart rate does not inherently describe normal sinus rhythm. Additionally, an irregular heartbeat suggests arrhythmias or other cardiac conditions, which are not consistent with the definition of normal sinus rhythm. Thus, regular rhythm stands out as the key characteristic that defines this normal physiological condition.