Given a scientific passage and an answer, generate a question for the given answer.
Q: Passage: Air enters the respiratory system through the nose. As the air passes through the nasal cavity, mucus and hairs trap any particles in the air. The air is also warmed and moistened so it won't harm delicate tissues of the lungs. Answer: mucus and hair
A:
In the nasal cavity, what 2 things trap particles from incoming air?