Define respiratory rate.

• A. The total lung capacity
• B. The amount of air moved per breath
• C. The number of breaths taken each minute
• D. The amount of air remaining after exhalation

Answer: (C)

Respiratory rate is the number of breaths taken each minute. It measures how often you breathe, not how much air you move with each breath. The amount of air moved per breath is called tidal volume, and together with respiratory rate it determines minute ventilation (minute ventilation = respiratory rate × tidal volume). Other terms describe lung capacity and remaining air after exhalation—for example, total lung capacity is the maximum air the lungs can hold, and residual volume is the air left after a full exhale. A typical resting rate for adults is about 12–20 breaths per minute, increasing with exercise or stress.