Final answer:
The epiglottis diverts food into the esophagus and prevents it from entering the lungs.
Step-by-step explanation:
The structure that diverts food into the esophagus and prevents it from entering the lungs is the Epiglottis. During swallowing, the epiglottis folds downward to cover the glottis, preventing food or liquid from entering the trachea. This ensures that food goes down the esophagus and into the stomach instead.