Correct Option
The correct option is Remove dust and foreign particles.
Explanation
The internal lining of the trachea, bronchi, and bronchioles is composed of ciliated epithelium. These epithelial cells possess microscopic, hair-like projections called cilia on their free surface, which are capable of rhythmic movement.
Detailed Analysis
- Remove dust and foreign particles is Correct: The primary function of ciliary movement in the respiratory tract is to propel mucus towards the pharynx (throat). The mucus traps dust, microbes, and other foreign particles inhaled from the air. The coordinated beating of cilia moves this particle-laden mucus upwards, away from the lungs, allowing it to be swallowed or expelled. This mechanism is often referred to as the "mucociliary escalator."
- Absorb oxygen is Incorrect: The absorption of oxygen occurs in the alveoli (air sacs) of the lungs through simple diffusion across the respiratory membrane, not through ciliary movement in the trachea.
- Glucose is Incorrect: Glucose is a metabolic fuel transported via the circulatory system. It is not handled or moved by the respiratory cilia.
- Bile is Incorrect: Bile is a digestive fluid produced by the liver and stored in the gallbladder. It functions in the digestive system for the emulsification of fats and has no role in the respiratory passage.
Key Takeaway
Ciliary movement in the trachea serves as a critical defense mechanism by facilitating the removal of dust and foreign particles trapped in mucus, thereby protecting the lungs from infection and obstruction.