Final answer:
Pneumonia is a disease in which the alveoli of the lungs become inflamed and filled with fluid due to infection. Aspiration of liquid into the lungs can cause an infection in the respiratory tract and lead to pneumonia.
Step-by-step explanation:
Pneumonia is a disease in which the alveoli of the lungs become inflamed and filled with fluid, usually as a result of infection. This can occur when liquid is aspirated into the lungs and causes an infection in the respiratory tract, leading to pneumonia.
For example, if someone inhales fluid or food particles while drinking or eating, it can enter the lungs instead of going down the esophagus. This can lead to the development of pneumonia.