Question

how diaphragm help in inspiration and expiration​

Answer 1

When you breathe in, or inhale, your diaphragm contracts (tightens) and moves downward. This increases the space in your chest cavity, into which your lungs expand. The intercostal muscles between your ribs also help enlarge the chest cavity. They contract to pull your rib cage both upward and outward when you inhale.

Answer 2

during inspiration diaphragm contracts to increase the pulmonary cavity and during expiration the diaphragm relaxs and becomes dome shaped to decrease pulmonary cavity