Final answer:
Hypersensitivity Pneumonitis is an occupational disease that occurs when the lungs become inflamed due to an allergic reaction to inhaled dust, endospores, bird feathers, bird droppings, molds, or chemicals.
Step-by-step explanation:
The subject of this question is Hypersensitivity Pneumonitis, which is a type of occupational disease that occurs when the lungs become inflamed due to an allergic reaction to inhaled dust, endospores, bird feathers, bird droppings, molds, or chemicals. It is sometimes called pigeon fancier's lung or poultry worker's lung when associated with bird droppings, and farmer's lung when associated with exposure to molds in farming environments.