The diaphragm in a rabbit is a:

Which of the following protects the lungs?

During swallowing,the glottis can be covered by a thin elastic cartilaginous flap called $A$ to prevent the entry of food into the larynx. The trachea is a straight tube extending up to the $B$ cavity,which divides at the level of the $5^{th}$ thoracic vertebra into right and left primary $C$. Choose the correct option for $A, B$,and $C$ from the given four options to complete the above statement with reference to the $NCERT$ textbook.

$A$ thin-elastic cartilaginous flap which prevents the entry of food into the larynx is known as

Definition / Explanation: $(1)$ Alveoli

Which one serves as a passage for both food and air?