A chemical barrier that is able to destroy the cell walls of certain harmful bacteria is the enzymes in tears. So, the correct option is D.
The cell wall is the outermost layer of a cell. It provides the cell with both structural support and protection. It is flexible, tough, and sometimes rigid.
Chemical barriers are those that destroy the outer surface of pathogens. Here, the enzyme lysozyme, found in tears has the ability to destroy the cell wall of certain harmful bacteria more frequently.
Therefore, A chemical barrier that is able to destroy the cell walls of certain harmful bacteria is the enzymes in tears.
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