Here's why:

* Formation: Sedimentary rocks are formed from the accumulation and cementation of sediments, like sand, mud, and organic matter. These materials are eroded from existing rocks, transported by wind, water, or ice, and eventually deposited in layers.

* Abundance: The processes of erosion and deposition are constantly reshaping the Earth's surface, leading to the formation of vast amounts of sedimentary rock.

* Location: Sedimentary rocks are found in many locations, including:

* Ocean floors: The vast majority of ocean floors are covered in sedimentary rock.

* Continents: Sedimentary rocks are also found in continental areas, often forming layers that can be thousands of feet thick.

While igneous and metamorphic rocks are also abundant, they are more commonly found in the Earth's crust and mantle.