* Sedimentary rocks are formed from the accumulation and cementation of sediments. These sediments can be:

* Physical processes: Weathering and erosion break down existing rocks into smaller pieces (sand, silt, clay).

* Chemical processes: Minerals dissolved in water precipitate out, forming new sedimentary rocks (like limestone).

* Build up plant and animal remains: Organic matter like shells, bones, and plant debris can accumulate and form rocks like coal.

* Lava cooling is the process that forms igneous rocks, not sedimentary rocks.

Let me know if you'd like more detail on any of these processes!