Answer;
Running water
Explanation;
Water is the most important erosional agent and erodes most commonly as running water in streams. However, water in all its forms is erosional.
Raindrops create splash erosion that moves tiny particles of soil. Water collecting on the surface of the soil collects as it moves towards tiny rivulets and streams and creates sheet erosion.
In streams, water is a very powerful erosional agent. The faster water moves in streams the larger objects it can pick up and transport.
