Asthma is?

Ans. is 'a' i.e., Obstructive lung disease o Obstructive disease is characterized by an increase in resistance to airflow owing to partial or complete obstruction at any level, from the trachea to the respiratory bronchioles. Examples are chronic obstructive lung disease (COPD emphysema, chronic bronchitis), bronchiectasis, and asthmao Restrictive disease is characterized by reduced expansion of lung parenchyma, with decreased total lung capacity. It may occur due to two types of disorders -a) Chest wall disorders in the presence of Normal lungs - Neuromuscular disorders, e.g.polio, severe obesity, pleural disease, kyphoscoliosis.b) Interstitial and infiltrative diseases of lung - Pneumoconiosis, interstitial fibrosis.