Final answer:
The normal respiratory rate for individuals aged 12 and older is between 12 to 18 breaths per minute, ensuring an effective exchange of oxygen and carbon dioxide in the lungs.
Step-by-step explanation:
The normal respiratory rate for a child changes as they grow, and it becomes similar to that of an adult by the time they reach adolescence. For individuals aged 12 and older, the typical respiratory rate is between 12 to 18 breaths per minute. This rate ensures efficient alveolar ventilation, which maintains the balance of oxygen and carbon dioxide in the blood. The ventilation control centers in the brain regulate this rate. While at rest, an average human breathes about 15 times per minute, and this rate might increase or decrease dependant on various conditions, such as physical exertion or illness.