Food is prevented from entering the trachea by the

A) pharynx.
B) larynx.
C) epiglottis.
D) glottis.
E) sphincter muscle.

The epiglottis is a flap of tissue that covers the trachea during swallowing, preventing food or liquid from entering the lungs. The pharynx and larynx are structures through which food and air pass, and the glottis is the opening into the larynx. A sphincter muscle may also help prevent food from entering the trachea, but it is not the primary mechanism for this.