a. Tidal Volume: Volume of air inhaled and exhaled during a normal breathing cycle without any forced breathing is tidal volume.The normal range of tidal volume in a young adult is 500 ml per inspiration.

b. Residual Volume:Volume of air left in the lungs even after forced exhalation is called as residual volume. The normal range of residual volume in a young adult is 1100-1200 ml.

c. Asthma:It is an inflammatory disease of the airways of the lungs. Due to which the airway gets narrowed and excess mucus secretion takes place resulting in breathing difficulty.

Symptoms of Asthma:

1. Wheezing

2. Breathing Difficulty

3. Coughing