Question

Explain that the largest organ in the body is also the body first line of defense against pathogens

Answer 1

skin is the largest organ.
the outer layer of skin is tough and has little water. Skin also secretes chemical such as lysozyme, lactic acid, fatty acid and antimicrobial peptides. The epithelial cells are joined with tight junctions and pathogen can't penetrate the skin easily. There is also normal flora on our skin. These methods prevent pathogen from entering our body.