Question

which of the following is a chemical barrier that is able to destroy the cell walls of certain harmful bacteria?
a. mucus membranes
b. skin
c. white blood cells
d. enzymes in tears

Explanation:

• Mucus membranes (A) and skin (B) are physical barriers, not chemical.
• White blood cells (C) are part of the immune - cell response, not a chemical barrier for destroying cell walls.
• Enzymes in tears (D), like lysozyme, are chemical barriers that can break down the peptidoglycan in the cell walls of certain harmful bacteria.

Answer:

D. enzymes in tears