Biology · Kingdom Animalia

The correct answer is A Lungs. In frogs, the process of respiration involves the use of both the nostrils and the lungs. When a frog breathes, new air is drawn into the bucco-pharyngeal cavity (the oral cavity and pharynx) through the nostrils. From there, the air moves into the lungs for gas exchange. 

In frogs, the new air is drawn into the buccopharyngeal cavity through the nostrils. From there, the air is passed into the lungs. Frogs utilize positive pressure breathing, which means they actively force air into their lungs by creating pressure in the buccopharyngeal cavity. The lungs are the primary respiratory organs responsible for gas exchange (oxygen uptake and carbon dioxide release) between the blood and the external environment. Old air is retained in the lungs for a short time and then expelled during exhalation as new air is drawn in during the next inhalation. Therefore, Option A is the correct answer.

Option B is not the correct answer. "Nasal" typically refers to the nose or the nasal cavity. While new air is drawn into the buccopharyngeal cavity through the nostrils, old air is not retained in the nasal cavity under pressure.

The glottis is the opening of the respiratory passage in frogs, located in the throat region. It functions as a valve that opens during breathing to allow air to pass into the lungs and closes during swallowing to prevent food from entering the respiratory system. However, the glottis is not responsible for retaining old air under pressure. Instead, it plays a role in controlling the passage of air into and out of the respiratory system. Therefore, Option C is not the correct answer.

Option D is not the correct answer. The trachea, also known as the windpipe, is a respiratory tube in vertebrates that connects the larynx to the lungs. In frogs, the trachea plays a role in conducting air to and from the lungs, but it is not directly involved in retaining old air under pressure.

Option E is not the correct answer. Nostrils, also known as nares, are the external openings of the nasal passages through which air is drawn into the buccopharyngeal cavity. While they are involved in the initial intake of new air, they are not responsible for retaining old air under pressure.