Q. Assertion : The lungs are situated in thoracic chamber which is anatomically an air-tight chamber.
Reason : Such an arrangement is essential to avoid any change in pulmonary volume.

 4999  204 Breathing and Exchange of Gases Report Error

Solution:

The lungs are situated in the thoracic chamber which is anatomically an air-tight chamber. The anatomical setup of lungs in thorax is such that any change in the volume of the thoracic cavity will be reflected in the lung (pulmonary) cavity. Such an arrangement is essential for breathing, as we cannot directly alter the pulmonary volume.