what is the transformation of the surface by agents external to the planet. They are classified into three large groups of phenomena: erosion, the transport of these particles, and their deposition.

The transformation of the surface by agents external to the planet refers to the process of weathering and erosion. This process is primarily driven by wind, water, and ice, which gradually wear down and carry away rocks and soil.

1. Erosion: This is the first step in the process. Erosion refers to the wearing away of the earth's surface by physical breakdown and chemical dissolution of rocks and minerals. The agents of erosion include water, wind, ice, and gravity. For example, water can cause erosion by creating rivers and streams that cut into the earth's surface. Wind can cause erosion by blowing away loose rocks and soil.

2. Transport: The second step in the process is the transport of these eroded particles. This is also done by the agents of erosion. For example, water not only causes erosion but also transports the eroded particles downstream. Wind can carry dust and sand great distances, and glaciers can transport large rocks over long distances.

3. Deposition: The final step in the process is deposition. This is when the transported particles are deposited or laid down in a new location. This often happens when the agent of erosion loses energy and can no longer carry the particles. For example, when a river slows down, it can no longer carry as much sediment and the sediment is deposited, creating features like river deltas.

These processes are constantly shaping and reshaping the earth's surface, and they play a crucial role in the formation of many of the earth's natural features.