1) when inhaling, there is a contraction of the intercostal muscles and diaphragm, the volume of the chest cavity increases;
2) the lungs passively stretch due to their elasticity and negative pressure in the pleural cavity, the air pressure in them becomes less than atmospheric;
3) during exhalation, relaxation of the intercostal muscles and diaphragm occurs, the volume of the chest cavity and lungs decreases, the air pressure in them increases.
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.