Definition: The total number of people divided by the total land area. This could be helpful to determine how crowded a country is.
It's so crowded that it's hard to breathe!
Arithemtic Density
Definiton: The number of people per unit of area of arable land. This could be helpful to determine how difficult a country may be settle in.
All of us have ran out of land, we are we going to settle?
Physiological Density
Definition: Total number of farmers per unit of arable land. This could be helpful to determine what countries are suitable for more farming and agriculture.
There are so many farmers that I have to share a barn with this guy standing next to me.