Completar frases Relief and rivers.Versión en línea Complete the sentences . por Esther Lara Barroso 1 initial curves plain rapidly slowly deposit rocks starting dragged flows slowly it less final Source : the point of the river . Upper course : the stage of the river in the mountains . The wáter flows and drags with it . Middle course : where the river flows more through landscapes that are steep , forming a flood . Lower course : in this stage the river and the rocks that it has with and forms called meanders .