Which disorder affects the air passages to the lungs and can be caused by bacteria or viruses?

The correct answer is bronchitis, which is an inflammatory condition affecting the bronchial tubes that lead to the lungs. It can result from various infectious agents, including bacteria and viruses. In acute bronchitis, these infections cause the air passages to become inflamed and produce excessive mucus, leading to symptoms like cough, wheezing, and difficulty breathing.

Understanding bronchitis is essential in the context of respiratory issues, as it differentiates from other conditions. For instance, while pneumonia is indeed caused by infections and affects the lungs, it typically involves inflammation of the lung tissue itself rather than just the air passages. Asthma, on the other hand, is primarily a chronic condition characterized by hyperreactive airways and is not directly caused by infections. Emphysema is a form of chronic obstructive pulmonary disease (COPD), primarily associated with long-term exposure to irritants such as cigarette smoke, rather than infections.

Knowing these distinctions helps clarify why bronchitis is the appropriate answer. It specifically highlights the role of infectious agents in creating inflammation in the air passages, making it unique among the conditions listed.