Cassandra and her mother have been playing patty-cake, but her mother is now trying to engage Cassandra in a picture book. Cassandra wants to play patty-cake again, so she grabs her mother's hands and puts them together as if in a clap. Cassandra is clearly in stage of sensorimotor development.

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