Final answer:
Children are diaphragmatic breathers throughout their life, beginning from infancy when the diaphragm is most prominently used, through adulthood as the respiratory system fully develops.
Step-by-step explanation:
Children are diaphragmatic breathers throughout their childhood into adulthood. Diaphragmatic breathing, which is also known as abdominal breathing, involves the diaphragm, a large muscle in the lower chest. Newborns and young infants primarily use their diaphragms for breathing, but as they grow and continue to develop, the intercostal muscles (muscles between the ribs) and accessory muscles of respiration play an increasingly significant role alongside the diaphragm.
The respiratory system, including the diaphragm and lungs, starts developing early in gestation and continues to mature into early childhood. By age 6 to 7, children typically breathe similarly to adults, with a full complement of mature alveoli and using a combination of diaphragmatic and intercostal muscles.
Thus, the diaphragm remains a key muscle for breathing throughout life. Therefore, Option 1, stating children are diaphragmatic breathers until age 2 is incorrect, as well as Option 2 (until age 6), and Option 3 (until age 10). The correct answer is Option 4, children remain diaphragmatic breathers throughout their life.