- Population Density - The number of organisms living per unit.
- Example - The population of France +6,000,000 people and the area is +551,000 square kilos. That means the population density of France is 109.8 people per square kilometer.
- For example in the tundra, if there are 25 hectares or 63 acres and 200 lemmings in that area, in one hectare there would be 8 lemmings.