The correct answer is B) population density.
The average number of individuals of a species per unit area is termed as population density. So, an area in a geographical location will be considered as densely populated if more number of people are residing in that region per unit area. But, if less number of people are residing in a particular per unit area then that region is termed as less dense. The human population density is measured in terms of number of individuals residing in per kilometer square area of a particular region. Currently, Monaco is the most densely populated country on the earth while population density is least in the polar regions like Greenland.
