Describe the function of the trachea.

The function of the trachea is primarily to serve as a passageway for air to the bronchi. It is a tube-like structure that extends from the larynx and branches into the left and right bronchi, which lead into the lungs. This anatomical configuration allows the trachea to effectively conduct air in and out of the lungs during respiration.

In regard to the other options, while the trachea does play a role in the overall process of respiration, it does not absorb oxygen directly from the air or connect the lungs to the diaphragm. Additionally, although it is involved in filtering air through its mucus lining, that is not its primary function, which is clearly defined as providing a clear airway for air transport.