How have don johanson and the leakeys contributed the search for early hominids?

The Leakeys made one of the first discoveries that early hominids possibly originated in Tanzania, Africa not Asia (which what anthropology thought at first).

Urban growth invariably feeds increased commercialization and industrialization. it requires continually expanding land areas. when urbanization rates are high, and countries do not have the institutional and managerial capacities or economic wherewithal to manage such rapid growths, they exert intense pressure on the types and nature of the resulting settlements. they contribute to the development of overcrowded slums and shanty towns without adequate essential services and necessary infrastructure.-by asit k. biswas and cecilia tortajada