What do saliva, tears, and nasal mucus have in common?

all can be classified as biological barriers.
all contain langerhans cells.
all can destroy bacterial cell walls.
all are part of the complement system.

The correct answer is that all can destroy bacterial cell wall. The saliva, tears, and nasal mucus has lysozyme which causes bursting in the pathognic cell membrane. It is an enzyme and is also called as muramidase, and is a part of the innate immunity system of the organsim.

The correct answer is that all can destroy bacterial cell wall. The saliva, tears, and nasal mucus has lysozyme which causes bursting in the pathognic cell membrane. It is an enzyme and is also called as muramidase, and is a part of the innate immunity system of the organsim.

The person who utilize the progression principle will keep adding the difficulty of the exercise that he's doing, while the person who does not, will only stay stagnant.  the person that utilize progression principle, will get a stronger endurance because now his body is conditioned to do harsher routines.{the answer was already on verified)