Which breathing process is active?

Which breathing process is active?

• A. Inhalation
• B. Exhalation
• C. Both inhalation and exhalation
• D. Neither

Answer: (A)

Inhalation is the active part of breathing because it requires muscular work to draw air into the lungs. When you inhale, the diaphragm contracts and moves downward while the external intercostal muscles lift the ribs, expanding the chest cavity and lowering the pressure inside the lungs. Air then flows in to equalize the pressure. Exhalation, in contrast, is passive at rest—the lungs and chest return to their resting size by elastic recoil, and air exits without muscular effort. Only during forced exhalation (like coughing or heavy breathing) do muscles actively push air out. So, the process that is active under normal conditions is inhalation.

Inhalation is the active part of breathing because it requires muscular work to draw air into the lungs. When you inhale, the diaphragm contracts and moves downward while the external intercostal muscles lift the ribs, expanding the chest cavity and lowering the pressure inside the lungs. Air then flows in to equalize the pressure. Exhalation, in contrast, is passive at rest—the lungs and chest return to their resting size by elastic recoil, and air exits without muscular effort. Only during forced exhalation (like coughing or heavy breathing) do muscles actively push air out. So, the process that is active under normal conditions is inhalation.