What is the part of the resporty tree which the alveoli are attched?

The alveoli are attached to the respiratory tree at the terminal bronchioles, which are the smallest branches of the bronchi. From the bronchioles, air passes into the alveolar ducts and then into the alveolar sacs, where the alveoli are clustered. This structure allows for efficient gas exchange between the air in the alveoli and the blood in the surrounding capillaries.