* Erosion: Streams are formed by the erosive power of water. Moving water wears away at the land, carving out channels and valleys. This process is called erosion.

* Deposition: As a stream flows, it carries sediment (like sand, silt, and gravel). When the stream slows down or reaches a wider area, it loses energy, and the sediment is deposited. This process is called deposition.

The interplay of erosion and deposition shapes a stream:

* Erosion: The stream erodes its channel, making it deeper and wider.

* Deposition: The stream deposits sediment to form features like floodplains, deltas, and alluvial fans.

So, while erosion is the initial force that creates a stream, deposition plays a vital role in shaping the stream's landscape and influencing its course.