<span>The correct answer is D. When you inhale the diaphragm contracts or tightens and moves downward. This increases the thoracic volume or the space in your chest cavity, giving your lungs room to expand as they fill up with air.</span>
D.The diaphragm contracts and thoracic volume increases.
Explanation:
During inhalation, the diaphragm and intercostal muscle contract which results in the expansion of the lungs. Due to this increase, the pressure is reduced. This decrease of pressure within the thoracic cavity as compared to the surroundings makes which creates a pressure gradient between the environment and the thoracic cavity. Due to the pressure gradient, air rush into the lungs
