Which of the following is a contributing factor to positional asphyxia?

Positional asphyxia occurs when a person's position prevents them from breathing adequately, typically due to obstruction of the airway or compression of the chest. Obesity is a significant contributing factor to positional asphyxia because excess body weight can increase the risk of airway obstruction and restrict the normal expansion of the chest during breathing. Individuals with obesity may have additional tissue around the neck and chest that can compromise their ability to breathe comfortably, especially when restrained or placed in certain positions.

The other options, such as being well-hydrated, staying active, and having good posture, do not contribute to this condition. In fact, staying active and maintaining good posture generally promote better respiratory function and reduce the likelihood of breathing difficulties. Being well-hydrated can aid overall health, including respiratory health, and therefore does not relate to an increased risk of positional asphyxia.