State the difference between inhalation and exhalation
*During INHALATION, the rib cage moves outwards and the diaphragm contracts to move downwards. As the rib cage expands, the space in the chest cavity increases allowing air rich in oxygen enter the lungs. *During EXHALATION, the ribs move inwards and the diaphragm relaxes to return to its normal position. The contraction of rib cage reduces the size of the chest cavity. Now air rich in carbon dioxide is driven out of the lungs.