What disease is characterized by mucus clogging the respiratory tract?

Cystic Fibrosis is the correct answer because it is a genetic disorder that leads to the production of thick, sticky mucus in various organs, most notably in the lungs. This mucus obstructs the airways, making it difficult for individuals to breathe and providing an environment conducive to infections. In Cystic Fibrosis, mutations in the CFTR gene affect the chloride channels in epithelial cells, resulting in abnormal ion transport and altered mucus properties. This characteristic mucus buildup is a hallmark of the condition, significantly impacting respiratory function.

Other conditions listed have different underlying mechanisms or causes. Emphysema primarily involves the destruction of alveoli due to long-term exposure to irritants, leading to difficulty in exhaling rather than mucus accumulation. Pleurisy is related to inflammation of the pleura surrounding the lungs and can be associated with pain and pleuritic breathing but does not involve mucus obstruction. Pulmonary edema involves fluid accumulation in the alveoli, affecting gas exchange but is not characterized by mucus buildup in the airways like Cystic Fibrosis.