Evaluating statements on human gas exchange

Steps:

• Identify the statements: Assume 1-4 refer to common facts (e.g., 1: alveoli site of exchange; 2: incorrect diffusion path; 3: oxygen binds hemoglobin; 4: wrong ventilation mechanism), but details missing.
• Check each: Verify 1 (alveoli enable diffusion) and 3 (hemoglobin transport) against biology.
• Eliminate pairs: Cross-reference with incorrect ones like 2 (trachea not for exchange) and 4 (diaphragm wrong action).
• Select matching pair: B combines verified 1 and 3.

Not enough information: Statements 1-4 not provided, preventing full verification.

Why B is correct:

• Matches definitions: Alveoli (1) are diffusion sites per Fick's law; hemoglobin (3) binds O2 via cooperative binding.

Why the others are wrong:

• A: Includes 2, false (gas exchange not in bronchi).
• C: Includes 4, incorrect (ventilation via diaphragm contraction, not expansion).
• D: Misses 1, omits key alveolar role.

Final answer: B