Answer :
The Agent-Host-Environment model is most useful in examining the cause of disease in an individual, based upon external factors.
What is a Disease?
They usually come with symptoms and affects the structure and functions of cells of the body.
The Agent-Host-Environment model helps in examining the cause of diseases as a result of external factors such as the agent which are mainly pathogenic micro-organisms.
Read more about Disease here https://brainly.com/question/1382377