Reasons.
Erosion and deposition occur side by side.

See explanation

Explanation:

Erosion occurs when the surface of the Earth is being washed away by water, wind etc. We should note that erosion and deposition works hand in hand.

Deposition simply follows after erosion has taken place. When sediments and rocks have been removed by erosion, deposition then startsas the particles settle in another place on a new surface on the Earth.

explanation:

since the crust is readily accessible, scientists have been able to perform hands-on experiments to determine its composition; studies on the more distant mantle and core have limited opportunities samples. so scientists also rely on analyses of seismic waves and gravity and as well as magnetic studies.