Final answer:
A floodplain is a flat area next to a river that floods periodically, leaving fertile sediments behind. Well-developed floodplains have distinct features from long-term sediment deposition, but without visuals it's impossible to identify the most developed one.
Step-by-step explanation:
Understanding Floodplains
A floodplain is a flat or nearly flat land adjacent to a stream or river that experiences occasional or periodic flooding. During such events, the floodplain becomes covered by water, which later recedes, leaving behind sediment. This fertile layer is beneficial for agriculture; however, floodplains can be hazardous areas for development due to their propensity for flooding.
The development of a floodplain occurs over time as the river deposits sediment during floods, expanding the flat area where water spreads. Consequently, well-developed floodplains are often wider and have more distinct depositional features such as meanders, oxbow lakes, and levees, indicating a long history of flooding and sediment deposition.