During inhalation, view available hint(s) during inhalation, oxygen molecules move into the lungs, and carbon dioxide molecules move out of the lungs. the volume of the thoracic cavity decreases. air moves up the trachea. the diaphragm relaxes. the diaphragm and rib muscles contract.

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.

when [oh-] is 10-5  m, and [h3o+] is 10-9  m, the poh is 5 and ph is 9. again in both cases the sum of ph and poh is 14. however, the hydrogen ion concentration is not always going to be equal to exactly 1 x 10 raised to a negative number. for example, we skipped over the value of 2.0 x 10-7.