Name a condition characterized by collapse of the alveoli.

Atelectasis refers to the collapse or partial collapse of the alveoli, which are the tiny air sacs in the lungs where gas exchange occurs. When atelectasis occurs, it prevents adequate oxygenation of blood, as the affected areas can no longer effectively participate in the exchange of oxygen and carbon dioxide. This condition can arise from various factors, such as obstruction by mucus, foreign objects, or tumors, as well as pressure from outside the lung or post-surgical complications.

In contrast, asthma is a chronic inflammatory condition that results in airway constriction but does not typically involve the collapse of alveoli. Pneumonia is an infection that inflames the alveoli but is characterized by the filling of these sacs with fluid rather than their collapse. Bronchitis involves inflammation of the bronchial tubes and is more associated with coughing and production of mucus, rather than the collapse of alveoli. Thus, atelectasis is the condition specifically recognized for the collapse of alveoli, making it the correct answer.