Increased breathing rate during exercise boosts CO2 removal

Steps:

• Exercise raises metabolic rate, producing more CO2 and consuming more O2.
• Deeper and faster breathing increases ventilation volume.
• This enhances gas exchange in lungs, removing CO2 and adding O2 to blood.
• Result: Blood pH stabilizes, and oxygen delivery to muscles improves.

Why A is correct:

• Breathing more deeply and frequently increases alveolar ventilation, which directly accelerates CO2 diffusion from blood to alveoli per Fick's law of diffusion.

Why the others are wrong:

• B: More breathing delivers more oxygen, which supports glucose transport to muscles via increased blood flow.
• C: Deeper breathing promotes overall heat loss through evaporation, not decreasing it in muscles.
• D: Faster breathing raises oxygen partial pressure gradient, increasing O2 diffusion into blood.

Final answer: A