The "city as a living organism" is a metaphor used in urban theory.
\textbf{Patrick Geddes} and \textbf{Lewis Mumford} are strongly associated with organicist theories of urbanism, emphasizing holistic, evolutionary, and environmentally integrated development.
\textbf{Le Corbusier}, a key figure in Modernism, also used biological analogies for the city, describing its functional components like organs of a body (e.g., "The Radiant City"). While often seen as mechanistic, he did employ this metaphor.
The choice depends on which theorist's specific use of the phrase or concept is being referenced by the question setters.