Which of the following is considered work performed by running water?

Running water is a powerful natural force that can change landscapes through various processes. Stream erosion is a specific and well-documented action performed by flowing water, where the kinetic energy of the moving water picks up, transports, and removes sediment and soil from the riverbank and bed. This process shapes the river's path over time, creating features like valleys and canyons.

In contrast, steel reinforcement involves construction techniques unrelated to the natural actions of water; vegetation growth is a biological process that occurs independently of water movement; and water absorption refers to the process of soil or other materials taking in water, which is not directly a result of running water's erosive action. Therefore, the defining characteristic of work performed by running water is clearly illustrated in stream erosion.