Final answer:
Emphysema is a respiratory disease characterized by the breakdown of the walls of the alveoli in the lungs. It is often caused by chronic smoking and leads to shortness of breath and difficulty in exhaling fully.
Step-by-step explanation:
Emphysema is a respiratory disease characterized by the breakdown of the walls of the alveoli in the lungs. This breakdown leads to the inability of air to move in and out of the lungs efficiently, resulting in shortness of breath and difficulty in exhaling fully. Emphysema is often caused by chronic smoking and is irreversible. Quitting smoking can help slow down the progression of the disease.