Yes , they are also very clean
In the past century, the world has recorded a rapid increase and decrease in population in different geographical areas. This has been influenced by different factors such as urbanization and family planning.
Urbanization creates better employment opportunities and wages. It also provides better social amenities such as schools and hospitals. These encourage people to move from rural areas to urban areas in search of a better living. The migration results in a decrease of population is the rural areas and a rapid increase in population in the urban cities.
Increased access to contraceptives has enabled women to limit family sizes. Women are able to plan for the number of children they intend to have. This has generally decreased the population growth in developed regions.
1. gravity keeps the water moving downward or just in general
2. the water has to move across the surface for so long till eventually it just erodes away.
those are the only two i know sorry.
