Problem: Naturally, the upper surface of the Mississippi Delta near what is now New Orleans: Need Assignment Help? Group of answer choices Sinks as its mud compacts, but the surface is built up by more mud from more floods Grows upward as mud from more floods is deposited Is lowered by erosion by floods Rises as it is inflated like a balloon by swamp gas Never changes in elevation because there is no erosion, deposition or compaction occurring