Difference between inhalation and exhalation

Breathing is brought about by inhalation and exhalation.
Mechanism of breathing in humans:
Air passes through the tiny hair in the nasal cavity. It enters pharynx and passes through larynx and windpipe before reaching the lungs.  Lungs are situated inside the chest cavity and they rest on a large muscular sheet called the diaphragm. Diaphragm forms the floor of the chest cavity. The diaphragm plays an important role in inhalation and exhalation. Movement of diaphragm is brought about by special musculature.

*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.