Dr. obsessa compulsa was a meticulous researcher. to make sure her assistants did not give any hints regarding which participants were in which treatment groups and to make sure her participants did not know which group they were in, she employed a:

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