Your outer skin is your epidermis, so just look at your arm
Bacteria have different phage resistance mechanisms, such as spontaneous mutations, the CRISPR-Cas system.
Spontaneous mutations are the main mechanisms leading to phage resistance by altering the structure of bacterial wall components that act as phage receptors. These include lipopolysaccharides (LPS), outer membrane proteins, cell wall teichoic acids, capsules, and other bacterial components.
Answer: c. molecular structure of DNA