Fill in the Blanks Relief and rivers.Online version Complete the sentences . by Esther Lara Barroso 1 starting initial curves deposit less final rapidly flows rocks plain slowly it slowly dragged 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 .