Breathing Increases During Exercise Steps:

• Recall that exercise raises oxygen demand, requiring faster and deeper breaths.
• Compare rest graph (baseline rate and depth) to options showing changes.
• Identify graph with elevated breathing rate (frequency) and depth (volume per breath).
• Select option matching both increases without distortions.

Why C is correct:

• C depicts higher breathing rate and depth, aligning with physiological law that exercise boosts ventilation to supply O2 and remove CO2 via increased respiratory minute volume.

Why the others are wrong:

• A: Shows only rate increase, ignoring depth change needed for full oxygen uptake.
• B: Displays only depth increase, neglecting rate acceleration for total volume.
• D: Indicates decreased or unchanged metrics, contradicting exercise demands.

Final answer: C