Which of the following is included in the lower respiratory tract?

The lower respiratory tract is defined as the portion of the respiratory system that includes the structures primarily involved in gas exchange. This area begins at the trachea and extends down to the lungs, encompassing the bronchi, bronchioles, and alveoli. Therefore, the left and right bronchi are indeed part of the lower respiratory tract as they branch off from the trachea and lead into each lung where gas exchange occurs.

The other options refer to structures that belong to the upper respiratory tract. The nose and nasal cavity, along with the trachea and larynx, are primarily involved in the initial filtering, warming, and humidifying of air, rather than gas exchange in the lungs. Similarly, the maxillary and frontal sinuses are part of the paranasal sinuses, which also serve different functions related to the upper airway. Understanding these anatomical differences is crucial in dive medicine, as they can impact scenarios such as equalization during descent and ascent in diving activities.