Describe the location and importance of cilia and mucus in the respiratory system.

Answer:

Mucus lines the respiratory passages, including the trachea and bronchi, where it traps dust, germs, and other particles. Tiny cilia lining these passages sweep the mucus toward the throat, where it can be swallowed or coughed out. Together, mucus and cilia help keep the lungs clean and protect them from infection and irritation.