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ATRITTION:material is moved along the bed of a river collides with other material, and breaks up into smaller pieces.CORRASION:fine material rubs against the river bank. The bank is worn away, by a sand-papering action called abrasion, and collapses.CORROSION:some rocks forming the banks and bed of a river are dissolved by acids in the water.HYDRAULIC ACTION:the sheer force of water hitting the banks of the river.TRACTION:large rocks and boulders are rolled along the bed of the river.SALTATION:smaller stones are bounced along the bed of a river in a sleap-frogging motion.SUSPENSION:fine materials,light enough in weight to be carried by the river.It is this material that discolours the water.SOLUTION:dissolved material is transported by the river. FREEZE-THAW:on cliffs above glacier.PLUCKING:on back wall as glacier moves away and downhill.ABRASION:moraine dragged by glacier erodes floor.MORAINE:rock debris that is usually angular and is transported and later deposited by a glacier