15. Which is the correct sequence of air passage during inhalation?
15. Which is the correct sequence of air passage during inhalation?

(a) Nostrils larynx pharynx trachea lungs

(b) Nasal passage trachea pharynx larynx alveoli

(c) larynx nostrils pharynx lungs

(d) Nostrils →pharynx →larynx →trachea →alveoli

The answer is (d) Nostrils →pharynx →larynx →trachea→alveoli

Explanation: Air enters the respiratory system through the nostrils, then travels through the pharynx, larynx, trachea, and alveoli. Following inhalation, the diaphragm and intercostal muscles contract, while the thoracic muscles expand, creating adequate space for air to enter the lungs.