What structure connects the pharynx to the lungs?

The trachea serves as the primary passageway for air, connecting the pharynx to the lungs. After air is inhaled through the nose or mouth, it moves into the pharynx, which then directs it into the trachea. The trachea is a flexible tube that extends downward into the thoracic cavity, where it bifurcates into the right and left bronchi, which lead into each lung. Functionally, the trachea is crucial for transporting air, ensuring that oxygen reaches the lungs where gas exchange occurs.

In relation to the other options, the bronchi are the branches that emerge from the trachea and enter into the lungs, but they do not directly connect the pharynx to the lungs. The esophagus is a separate structure that carries food from the throat to the stomach, not air to the lungs. Alveoli are the tiny air sacs located in the lungs where gas exchange occurs, but they do not connect the pharynx to the lungs directly. Each of these structures plays an important role in the respiratory and digestive systems, but the trachea specifically functions to convey air directly from the pharynx down into the lungs.