The correct answer is - A. reduce the amount of sediment deposited on floodplains and increase the amount of sediment deposited at the river's mouth.
The Mississippi River is one of the biggest rivers in the world. It is also a river that carries with it very large amount of sediments. The levees built along side it though do not allow the natural process of deposition of sediments on the floodplains of the river. That results in the river carrying the sediments down to the river mouth. Because of this, the river mouth is becoming an ever-growing delta because of the constant deposition of very large amounts of sediments. This also causes lot of the sediments to end in the coastal parts of the sea, which makes the sea waters shallower and murkier, as well as creating new land forms alongside the coast from the deposited material.
I think the phrase you are looking for is "natural resources" - these include fresh water, food and fertile soil on which crops can easily be planted.
it is the benthic zone , that's the answer
They can be replaced naturally.
