Which disease is characterized by constriction of airways and difficulty in breathing?

Asthma is characterized by constriction of the airways, which leads to difficulty in breathing. This condition is often triggered by allergens, exercise, cold air, or respiratory infections, causing inflammation and narrowing of the bronchial tubes. The hallmark symptoms of asthma include wheezing, coughing, chest tightness, and shortness of breath, particularly during an asthma attack when the airways become significantly restricted.

In contrast, chronic bronchitis primarily involves persistent cough and mucus production due to long-term inflammation of the bronchial tubes but does not typically involve the same acute constriction as asthma. Pneumonia is an infection that inflames the air sacs in one or both lungs, which can lead to breathing difficulties but is characterized more by cough, fever, and chest pain than direct airway constriction. Heart failure involves the heart's incapacity to pump blood effectively but, while it may lead to pulmonary congestion and difficulty breathing, it is not primarily defined by airway constriction like asthma is.

Therefore, asthma distinctly features the acute airway constriction that results in the difficulty in breathing, making it the correct answer to the question.