Here's why:

* Sedimentary Rocks: These rocks are formed from the accumulation and cementation of sediments, which are fragments of other rocks, minerals, or organic matter.

* Conglomerates: Conglomerates are specifically a type of sedimentary rock composed of rounded fragments of gravel-sized or larger rocks (pebbles, cobbles, or boulders) that have been cemented together.

So, the process of forming conglomerates involves the weathering and erosion of existing rocks, the transportation and deposition of those fragments, and finally, their lithification (compaction and cementation) into a solid rock.