Insect vs. Human Gas Exchange Differences

Steps:

• Statement 1: Insect tracheae allow direct diffusion to cells; human alveoli require blood transport.
• Statement 2: Insect tracheae contain chitin for rigidity; human airways use cartilage and muscle.
• Statement 3: Insects have a branching network of many tracheae; humans have a single trachea that bifurcates into bronchi.
• All statements correctly identify unique structural and functional aspects.

Why A is correct:

• A includes all three statements, matching the definition of insect tracheal system (direct, chitin-lined, multi-tracheal) versus human pulmonary system (indirect, non-chitin, single trachea).

Why the others are wrong:

• B omits statement 3, but insects indeed have multiple tracheae while humans have one.
• C omits statement 1, but direct gas exchange to cells occurs only in insects.
• D omits statements 1 and 2, ignoring key functional and material differences.

Final answer: A