Final answer:
The pathogen's method of getting from one person to another in the chain of infection is known as transmission. Pathogens can be transmitted through several pathways such as vertical, sexual, and airborne transmission, or through indirect contact with fomites.
Step-by-step explanation:
The chain of infection requires that a pathogen have a physical way of getting from one person to another. This is the pathogen's method of transmission. Pathogens can be transmitted through various routes, including vertical transmission from an infected woman to her offspring, sexual transmission through sexual activity, and airborne transmission when infected droplets are inhaled by others. Additionally, pathogens can spread through indirect contact transmission by way of fomites, or non-living objects. Exposure to potential pathogens can happen through various portals of entry into the body, like the skin and mucous membranes, which can lead to infection.