Question

What is the definition of atmospheric pressure-best explained?

Answer 1

I Hope it helps you. That's all

Answer 2

$\huge\mathfrak\color{blue}{Answer}$

The pressure drops to below atmospheric pressure (negative gauge pressure) when you inhale, causing air to flow into the lungs. It increases above atmospheric pressure (positive gauge pressure) when you exhale, forcing air out. Lung pressure is controlled by several mechanisms.