Final answer:
The correct option is 4 ). The epiglottis forms a lid over the glottis by folding down during swallowing to prevent food and drinks from entering the airway.
Step-by-step explanation:
The structure that forms a lid over the glottis is the epiglottis. The thyroid cartilage, which includes the laryngeal prominence or "Adam's apple," is anterior to the larynx. The thick cricoid cartilage forms a complete ring below the thyroid cartilage, while the arytenoid cartilages are small paired cartilages that function in the movement of the vocal cords. When swallowing, the larynx moves upward, and the epiglottis folds down to cover the opening to the trachea, preventing food and liquids from entering the airway.