Factors Reducing Lung Surface Area for Gas Exchange

Steps:

• Identify key factors affecting alveolar surface area in lungs.
• Evaluate statement 1: Emphysema destroys alveolar walls, reducing surface area.
• Evaluate statement 2: Pulmonary fibrosis thickens alveolar walls, impairing gas exchange surface.
• Evaluate statement 3: Asthma causes airway constriction but does not directly reduce alveolar surface area.

Why B is correct:

• B links emphysema (1) and fibrosis (2) directly to alveolar damage reducing gas exchange area, per respiratory physiology definitions.

Why the others are wrong:

• A includes 3, but asthma affects airways, not surface area.
• C pairs 1 with 3, excluding fibrosis's direct impact.
• D pairs 2 with 3, excluding emphysema's alveolar destruction.

Not enough information on exact statements 1-3 to confirm beyond standard biology.

Final answer: B