They are formed in layers and derived from old rocks and the remains of dead organic materials. This description refers

Sedimentary rocks form in layers over millions of years. They come from broken pieces of old rocks and dead plants or animals.

Igneous rocks come from cooled lava or magma. Metamorphic rocks form when other rocks change under heat and pressure.

The word “sediment” means material that settles in layers at the bottom of water or land.