Final answer:
Asthma is a chronic inflammatory disease of the airways characterized by bronchial spasms. It is caused by allergens and leads to difficulty breathing.
Step-by-step explanation:
Asthma is a chronic inflammatory disease of the airways in the lungs, characterized by constriction of the bronchioles and difficulty breathing. When an allergen triggers an asthma attack, the smooth muscles surrounding the bronchi spasm, narrowing the airways. This leads to symptoms such as chest tightness, wheezing, and difficulty breathing.