A delta is an area of land that forms where a river flows into a sea or lake. As t river rea the op water, i slows do and dr the m and sa it h been carr. Over time, these materials build up and create new land, which often has the shape of a triangle. Delta soil is usually very fertile, so deltas have long been important for farming. However, many deltas are now sinking or shrinking because dams upstream trap the mud that would normally reach them.

Type only the missing letters. Each box is one letter, and the number of boxes matches the letters that are missing.