What connects the mouth to the lungs in frogs during respiration?

The glottis serves as a crucial structure that connects the mouth to the lungs in frogs during respiration. This opening, located at the back of the mouth, allows the frog to take in air through the mouth and direct it into the lungs. The glottis opens when the frog inhales, facilitating the passage of air, and closes when the frog exhales to prevent air from escaping.

The trachea, while it is indeed a tube that carries air from the glottis to the lungs, is not the correct answer in this specific context, as it is not directly linking the mouth and lungs. The Eustachian tube is associated with equalizing pressure in the ear and is not involved in the respiratory process in frogs. The pharynx, although an area connecting the mouth and various respiratory and digestive pathways, does not specifically connect the mouth to the lungs in the manner that the glottis does during respiration.