Answer: Gorge
Notes: The river is often divided into three parts or stages: (a) Upper course (steep gradient): Tributaries; V-Shaped valley; Interlocking spurs; Waterfalls; Rapids; Gorges (b) Middle course (gentle gradient): Lateral (sideways) erosion starts; Transportation, River beaches; Meanders; River cliffs (c) Lower course (very low gradient): Deposition Flood plain; Ox-bow lakes; Levées; Delta; Estuary
