If you are relating the levels of organizations the human body to the levels of organization of a city, what would relate cells to?

maybe a factory since there are amun components and everyone works together to make sure everything goes right

a "theory" a suggestion that is not 100 % accurate, or a figure. some people say its a theory because they of all the passed theory's about one subject. it depends sometimes theory might be accurate and sometimes they are.

organ system-an organ system is a group of organs that work together to perform one or more functions. each does a particular job in the body, and is made up of certain tissues.