Answer:
The correct statement is C The diaphragm"s movement downward to draw air into the lungs shows how muscles are necessary to bring air intto the body.
Explanation:
Diaphragm is important part of the respiratory system.During inhalation of oxygen diaphragm moves downward with the help of adjacent respiratory muscle by the same way during exhalation diaphragm moves upward to diffuse the carbon dioxide out of the body.
Diaphragm along with respiratory muscles play an important role in proper gas exchange.