Explanation:

Asthma is a chronic respiratory condition characterized by difficulty in breathing, wheezing, coughing, and tightness in the chest. It is caused by inflammation and narrowing of the airways in the lungs, making it hard to breathe.

The allergic reaction of the mast cell in the lungs is the primary cause of asthma. The mast cell is a type of immune cell that is present in the airways of the lungs. When a person with asthma is exposed to an allergen, such as dust, pollen, or animal dander, the mast cells in the lungs release chemicals such as histamine, leukotrienes, and prostaglandins.

These chemicals cause inflammation and constriction of the airways, leading to symptoms of asthma. The inflammation and narrowing of the airways can be chronic or episodic, and it can be exacerbated by environmental factors such as pollution, cold air, and exercise.

In addition to allergic reactions, other factors that can contribute to asthma include:

- Genetics: Asthma tends to run in families, and certain genes have been identified that increase the risk of developing the condition.
- Environmental factors: Exposure to air pollution, tobacco smoke, and certain chemicals can increase the risk of developing asthma.
- Respiratory infections: Viral infections such as the common cold and flu can trigger asthma symptoms.
- Stress: Emotional stress can trigger asthma symptoms in some people.

In summary, asthma is primarily caused by an allergic reaction of the mast cell in the lungs, which leads to inflammation and narrowing of the airways. Other factors that can contribute to asthma include genetics, environmental factors, respiratory infections, and stress.