Final answer:
Unpasteurized milk from an infected cow is an example of a vehicle factor in the transmission of disease, serving as an intermediary to carry the pathogen to a human host.
Step-by-step explanation:
Unpasteurized milk from an infected cow is an example of a vehicle factor in the transmission of disease. The vehicle transmission method refers to the transfer of pathogens through contaminated food, water, air, or bodily fluids from an infected host. In this case, the milk serves as a non-living intermediary (vehicle) that carries the pathogen from the infected cow to a human host. This is different from a vector, which would be a living organism that transmits the infection; a fomite, which is an inanimate object that aids in transmitting the disease; and a reservoir, which is the primary habitat in which the pathogen lives.