Together, the trachea and the two primary bronchi are referred to as the bronchial tree. At the end of the bronchial tree lie the alveolar ducts, the alveolar sacs, and the alveoli. The tubes that make up the bronchial tree perform the same function as the trachea: they distribute air to the lungs.
Selective breeding is when a human or farmer in this case selects two plants or chickens with the best traits in order to get a good yield and quality for the products they are producing. I hope this helps!
