Step 1: Ernest Burgess's 1920 Concentric Zone model outlines how urban areas are structured in rings radiating from the central business district (CBD).
Step 2: Immediately surrounding the CBD is the Zone of Transition, featuring a mix of residential and commercial properties, substandard housing, and frequent social and economic shifts.
Step 3: Outer zones, including the Zone of Independent Working Class and the Zone of High-Class Homes on the city's edge, are progressively more residential and stable, with less mixed-use development.
Conclusion: In Burgess's model, the Zone of Transition is defined by its combination of residential and commercial establishments.