A(n) __________ is a large deposit of sediment at the mouth of a river.

A delta is a large deposit of sediment that builds up where a river flows into a larger body of water, such as a lake or ocean. A rift valley is a landform formed by movement of Earth’s crust, while a sand dune is a mound of windblown sand and an estuary is a coastal area where river water mixes with seawater.

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