How is breathing rate defined?

Breathing rate is defined as the number of breaths taken per minute, which is accurately represented by the correct answer. This measurement reflects how frequently an individual inhales and exhales within a one-minute duration, providing valuable insight into respiratory health and fitness levels. Breathing rate can fluctuate based on various factors, including physical activity, emotional state, and overall health.

The other options relate to different aspects of respiration. The number of beats per minute pertains to heart rate, while the volume of air inhaled refers to tidal volume. Depth of each breath concerns the intensity and fullness of inhalation and exhalation, neither of which directly define the breathing rate itself. Thus, focusing on the number of breaths taken within a specified time frame captures the essence of breathing rate effectively.