Your thoracic cavity increases in size when O your abdominal muscles contract. O both sets of your intercostal muscles relax. O your diaphragm and a set of intercostal muscles contract. O your diaphragm relaxes. O your lungs expand through elastic recoil. . Refer to the figure. Maximum nhalation Maximal tidal volume MAN Total lung capacity Maximum exhalation This tracing from a spirometer is from a person who breathes in and out a maximum of of air but at rest breathes in and out about O 6 liters; 2 liters of air per breat O 5 liters; less than 1 liter O 6 liters; 1 liter O 6 ml; less than 1 ml O 4 liters; less than 1 liter Volume (liters) 2.