Which statement best describes the diaphragm's function?

Which statement best describes the diaphragm's function?

• A. Pumps blood through heart
• B. Aids digestion
• C. Helps lungs expand and contract
• D. Filters toxins

Answer: (C)

The diaphragm is the main muscle behind breathing. It sits under the lungs and, as it contracts, moves downward to flatten and enlarge the chest cavity. This increase in space lowers the air pressure inside the thorax, so air rushes into the lungs to fill them. When the diaphragm relaxes, it moves back up, narrowing the chest cavity and helping air be pushed out as you exhale. This action is what allows the lungs to expand and contract with each breath, making that statement the best description of its function. The diaphragm isn’t responsible for pumping blood, aiding digestion, or filtering toxins.

The diaphragm is the main muscle behind breathing. It sits under the lungs and, as it contracts, moves downward to flatten and enlarge the chest cavity. This increase in space lowers the air pressure inside the thorax, so air rushes into the lungs to fill them. When the diaphragm relaxes, it moves back up, narrowing the chest cavity and helping air be pushed out as you exhale. This action is what allows the lungs to expand and contract with each breath, making that statement the best description of its function. The diaphragm isn’t responsible for pumping blood, aiding digestion, or filtering toxins.