What do saliva, tears, and nasal mucus have in common? a .all can be classified as biological barriers. b .all contain langerhans cells. c .all can destroy bacterial cell walls. d. all are part of the complement system.

All can destroy bacterial cell walls.

C. All can destroy bacterial cell wall.

Saliva, tears and nasal mucus are physical and chemical barriers which are produced by the body as a defense against pathogens like bacteria and viruses. Saliva, tears and nasal mucus all these biological fluids which are secreted by mouth, eyes and nose. They release enzymes that breaks down the cell walls of bacteria and prevent their action on the body.