Glottis is closed during swallowing of food bolus by...........

Explanation

**Step-by-Step Solution:**

1. **Understanding the Question:**
The question asks about the mechanism that prevents food from entering the respiratory tract during swallowing. Specifically, it inquires about what closes the glottis during this process.

2. **Identifying the Relevant Anatomy:**
The glottis is the opening between the vocal cords in the larynx. It plays a crucial role in both breathing and swallowing. During swallowing, it is essential to prevent food from entering the trachea.

...