Final answer:
The structure that bars food and liquids from entering the trachea during swallowing is the epiglottis.
Step-by-step explanation:
The structure that bars food as well as liquids from getting into a person's trachea at the time of swallowing is the epiglottis.
During swallowing, the epiglottis covers the opening to the trachea, called the glottis, preventing food from entering the trachea. This allows food to pass safely into the esophagus and on to the stomach.
The epiglottis is a flap of elastic cartilage located in the larynx, which is a cartilaginous structure connecting the pharynx to the trachea.