Answer: C) Wetlands act as sediment sinks (or basins).
Wetlands improve water quality in an ecosystem by acting as sediment sinks (or basins).
Wetlands filter water through their role in water flow. They act as a sediment sink depending on particle sizes, the concentration of the sediment load and flow velocity. The sediments which pass through wetlands will drop out of the water and become part of its ground layer. In this way, the water becomes clear and sediment is removed. Wetlands naturally reduce nutrient runoff also.