Here's why:

* Weathering is the process where existing rocks (igneous, metamorphic, or even other sedimentary rocks) are broken down into smaller pieces. This can happen through:

* Physical weathering: Forces like wind, water, ice, or temperature changes break rocks apart.

* Chemical weathering: Reactions with water, acids, or oxygen dissolve or alter the rock's minerals.

This breakdown creates the sediments (sand, silt, clay, etc.) that will eventually form sedimentary rocks.