(a) Food plains: It is found at the lower course of a river and generally low lying. During floods, large quantities of materials are transported the upper course of the river and these materials are spread over low lying adjacent areas. 4. layer of sediments gradually builds up the flood plain usually very fertile. It is dangerous for human habitation. Examples are Ganges Plain, Mississippi, Hwang-Ho etc
(b) Hydrological Cycle: This is the movement of water through a series of processes - evaporation, transportation and precipitation. When it rains, some water immediately evaporate back to the atmosphere, while some are absorbed by plants and gradually return to the atmosphere by way of transpiration. Some water run off the slopes and rivers and flow back to seas and oceans while some evaporate directly from the ground to the atmosphere. Clouds are also formed, then rains are formed in the atmosphere and water sent back to the ground and some water percolate in the ground to form ground water.