(a) Colonialism (b) Industrialisation (c) Urbanisation.
(a) Colonialism: Colonialism simply means the establishment of rule by one country lover another. In the modern period western Colonialism has had the greatest impact.
(b) Industrialisation: Industrialisation refers to the emergence of machine production, based on the use of inanimate power resources like steam or electricity. A prime feature of industrial societies today is that a large majority of the employed population work in factories, offices or shops rather than agriculture.
(c) Urbanisation: Urbanisation it is process of migration of population from rural areas and smaller towns to bigger towns and cities on a large scale due to social, economical and political causes.