Bronchi is delivering air from outside the body, enters the lungs to function in gas exchange of oxygen into the blood and bring the carbon dioxide out of the body.
Bronchial main function is to deliver air to the lungs outside the body to act on the exchange of oxygen into the blood. And take carbon dioxide out of the body.
The trachea is the main function is transport of air from the outside of the body into the lungs to act in exchange of oxygen into the blood. The carbon dioxide out of the body.