Final answer:
The subject of this question is the normal respiratory rate of infants.
Step-by-step explanation:
In the context of this question, the subject being discussed is the normal respiratory rate of infants.
The normal respiratory rate of a child decreases from birth to adolescence. A child under 1 year of age has a normal respiratory rate between 30 and 60 breaths per minute, but by the time a child is about 10 years old, the normal rate is closer to 18 to 30. By adolescence, the normal respiratory rate is similar to that of adults, 12 to 18 breaths per minute.