What characteristic of a population increases with plentiful resources:
a. range
b. clumping
c. spatial distribution
d. population density

d. population density

Population density refers to the amount of population per unit area or unit volume. Most densely populated territories in the world are city-states and microstates. These territories usually have a small area, but with a high level of urbanization, and are economically stable. For these reasons, inhabitants draw nearer to them. 

Ais the correct answer