Answer:
the diaphragm and rib muscles contract
Explanation:
Inhalation is the set of movements that allows air to enter the lungs. In this process occurs the contraction of the diaphragm, causing its lowering. The intercostal muscles also contract causing the ribs to lift. This causes the chest to grow larger and the internal pressure of the lungs to become smaller than the external. With the reduction of intrapulmonary pressure, air ends up entering the airways and reaching the alveoli for gas exchange to occur.