Which of the following characteristics of the pediatric respiratory system makes infants and young children more susceptible to respiratory distress compared to adults?

A. Smaller airway diameter and immature respiratory muscles is correct because infants and young children have narrower airways, making them more prone to obstruction from edema, mucus, or inflammation. Additionally, their respiratory muscles, including the intercostals, are underdeveloped, so they rely heavily on diaphragmatic breathing. These factors increase the risk of respiratory distress during illness or airway compromise. B. More developed diaphragm and increased lung compliance is incorrect because infants have a less developed diaphragm and less compliant chest wall, not more. This makes breathing less efficient and increases susceptibility to fatigue and distress. C. Larger airway diameter and more developed lung volume is incorrect because infants have smaller airway diameter and smaller lung volumes compared to adults, which contributes to rapid desaturation during respiratory compromise. D. Larger alveolar surface area and stronger respiratory muscles is incorrect because infants have fewer alveoli and weaker respiratory muscles, which limits gas exchange and makes them more vulnerable to hypoxia.