What is the common passage for food and air in the human respiratory system?

Step-by-step solution

We have a pair of external nostrils opening out above the upper lips. It leads to a nasal chamber through the nasal passage . The nasal chamber opens into the pharynx, a portion of which is the common passage for food and air. The pharynx opens through the larynx region into the trachea. Larynx is a cartilaginous box which helps in sound production and hence called the sound box. During swallowing glottis can be covered by a thin elastic cartilaginous flap called epiglottis to prevent the entry of food into the lar