* Mass is conserved: The total amount of matter in a closed system remains constant, even if it changes form.
* Erosion and transport: When mountains erode, the rock material doesn't disappear. It's simply broken down into smaller particles (sediments) and transported by streams.
* Total mass remains the same: The total mass of the eroded rock material (sediments) plus the mass of the stream (water) remains constant throughout the process. Even though the rock material has been moved, its total mass hasn't been created or destroyed.
Therefore, the conservation of mass is illustrated by the movement of sediments from mountains to streams.
