Question

upward amd downward movement of diaphragm occurs consecutively.

Answer 1

Upper and downward movement of diaphragm occurs consecutively dueing respiration. When we inhale air the diaphgram moves upward and when we exhale air the diaphgram moves downward.

Answer 2

The upward and downward movement of diaphragm occurs consecutively during inspiration process.

It is because when you inhale the air, diaphragm in your breathing system moves fully upward and while you exhale the air, diaphragm fully moves download.

Apart from that, the diaphragm can contracts as well as pulls downward when your muscles actually between ribs contract while pulling upward.