Two.Breathing out (expiration) the diaphragm will move higher. Ribs will slide down. The volume of the chest cavity is reduced. Air pressure around the lungs is higher than the outside air.
2. Breathing out (Expiration), the diaphragm moves up the lower rib, chest cavity volume decreased. The air pressure in the area surrounding the lungs is higher than the air outside.
2.The breath out (Expiration), the diaphragm will move up the ribs to move down to lower volume of the chest, the air pressure in the area around high-lung than outside air.