Q: Context: Several of the most densely populated territories in the world are city-states, microstates and dependencies. These territories have a relatively small area and a high urbanization level, with an economically specialized city population drawing also on rural resources outside the area, illustrating the difference between high population density and overpopulation.

Question: where do population densities on earth tend to be higher?
Let's give stream of consciousness below
The relevant information to answer the above question is: Several of the most densely populated territories in the world are city-states, microstates and dependencies. So the answer is city - states , microstates and dependencies.