Question

the mucus-covered ____ keep unwanted particles out of the lungs. white blood cells red blood cells cilia plasma

Explanation:

• White blood cells are involved in immune response, not filtering particles from lungs.
• Red blood cells carry oxygen, not related to particle filtration.
• Cilia are hair - like structures in the respiratory tract, covered in mucus, and they move to sweep unwanted particles out of the lungs.
• Plasma is the liquid part of blood, not involved in lung particle filtration.

Answer:

C. cilia