Final answer:
The correct answer is A) Nostril; to filter dust and particles. The nostril is the opening of the nasal cavity, and hairs within this structure function to filter and trap particles from the air to protect the respiratory tract.
Step-by-step explanation:
The Opening of the Nasal Cavity and the Function of Hair
The opening of the nasal cavity is called the nostril. It serves as the initial entry and exit point for air in the respiratory system. Within the nostrils, there are hairs that have the primary function of filtering dust and other particles from the air we breathe. This helps to protect the deeper structures of the respiratory system from potential contaminants.
The nasal cavity is a continuation of the two nostrils and plays a crucial role in respiratory health by warming, humidifying, and filtering the air. The hairs within the nasal cavity trap large foreign particles, while the mucous membrane helps trap smaller particles, both contributing to a cleaner breathing path to the lungs.
Therefore, the correct answer to the student's question is A) Nostril; to filter dust and particles. This basic knowledge about the respiratory system and nasal cavity is important for understanding human anatomy and maintaining respiratory health.