Bronchioles' structural and functional features

Steps:

• Identify key bronchioles traits: no cartilage, smooth muscle walls, regulate airflow to alveoli.
• Assume statement 1: bronchioles lack cartilage (true, unlike bronchi).
• Assume statement 2: bronchioles have goblet cells (false, they lack mucus-producing cells).
• Assume statement 3: bronchioles lead to alveolar ducts (true, part of respiratory zone transition).
• Select combination matching truths: 1 and 3.

Why C is correct:

• C (1 and 3 only) aligns with bronchioles' definition as non-cartilaginous airways branching to alveoli, per respiratory anatomy.

Why the others are wrong:

• A includes 2, but bronchioles lack goblet cells, unlike larger airways.
• B includes 2 but excludes 3, missing bronchioles' role in alveolar airflow.
• D excludes 1, ignoring absence of cartilage in bronchioles.

Not enough information on exact statements, but based on standard facts.

Final answer: C