Question

upward and downward movement of diaphragm causes consecutively

Answer 1

Hey mate here is ur answer : -
The upward and downward movement of diaphragm causes 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 downward.
Hope it helps u : -)

Answer 2

When you breathe in, the diaphragm contracts downward, creating a vacuum that causes a rush of fresh air into the lungs. The opposite occurs with exhalation, where the diaphragm relaxes upwards, pushing on the lungs, allowing them to deflate.