Due to increasing air-borne allergens and pollutants,many people in urban areas are suffering from respiratory disorders causing wheezing due to:

• A
  benign growth on the mucous lining of the nasal cavity.
• B
  inflammation of bronchi and bronchioles.
• C
  proliferation of fibrous tissues and damage of the alveolar walls.
• D
  reduction in the secretion of surfactants by pneumocytes.