Increase in minute ventilation volume

Steps:

• Calculate resting minute volume: 12 breaths/min × 500 cm³/breath = 6000 cm³/min.
• Calculate exercise minute volume: 24 breaths/min × 1000 cm³/breath = 24000 cm³/min.
• Subtract resting from exercise volume: 24000 cm³/min - 6000 cm³/min = 18000 cm³/min.
• The increase is 18000 cm³, representing total volume change per minute.

Why C is correct:

• C equals the difference in minute ventilation (breaths/min × volume/breath), the standard measure of total breathing volume.

Why the others are wrong:

• A: Matches exercise breath volume, not the increase.
• B: Equals resting minute volume, not the change.
• D: Equals exercise minute volume, not the increase.

Final answer: C