Positive feedback loops are caused: A. when a small physiological change leads to an amplified change in the same direction. B. when the body responds to cold temperatures by shivering and constricting blood vessels near the skins surface. C. when a physiological change in one direction leads to a change in the opposite direction. D. when physiological changes no longer occur in the cell.

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