Which condition is characterized by narrowed breathing passages?

The condition characterized by narrowed breathing passages is indeed asthma. Asthma is a chronic respiratory condition where the airways become inflamed and narrow, making it difficult for air to flow in and out of the lungs. This narrowing can be triggered by various factors, including allergens, exercise, cold air, or respiratory infections, leading to symptoms such as wheezing, shortness of breath, chest tightness, and coughing.

While pneumonia, croup, and bronchitis are all respiratory conditions, they do not primarily involve the chronic narrowing of airways in the same way as asthma. Pneumonia is an infection that inflates the air sacs in the lungs and can lead to fluid accumulation. Croup is an illness that causes inflammation of the upper airways, typically affecting children, and is characterized by a distinctive barking cough but is more about upper airway obstruction rather than primarily narrowed passages. Bronchitis involves inflammation of the bronchial tubes, leading to increased mucus production, but it is not characterized by the same chronic constriction of the air passages seen in asthma.