Density of population is expressed as number of persons per unit area.
Density of Population = Population/Area
Four geographical factors that influence the distribution of population in the world :
1. Availability of water: It is the most important factor for life. So, people prefer to live in areas where fresh water is easily available.
2. Landforms: People prefer living on flat plains and gentle slopes. This is because such areas are favourable for the production of crops and to build roads and industries.
3. Climate: An extreme climate such as very hot or cold deserts are uncomfortable climate, but where there is not much seasonal variation, attracts more people.
4. Soil: Fertile soils are important for agricultural and allied activities. Therefore, areas which have fertile loamy soils have more people living on them as these can support intensive agriculture.