Which statement describes sedimentary rocks?

• A. Form from cooling magma
• B. Form from broken pieces of preexisting rock, organic material that solidifies, or from material that precipitates from a water solution
• C. Form from heating and squeezing existing rocks
• D. Form when rocks crystallize from melted material

Answer: (B)

Sedimentary rocks form when materials are deposited and then turned into rock through compaction and cementation. These materials come in three main kinds: fragments broken from preexisting rock (clastic sediments), organic matter that accumulates and lithifies into rocks like coal, and minerals that precipitate from water solutions to form chemical sediments. The statement describes exactly these pathways: rocks formed from broken pieces of preexisting rock, from solidified organic material, or from materials that precipitate out of water.

The other processes describe igneous or metamorphic rocks—cooling magma forms igneous rocks, heating and squeezing existing rocks transforms them into metamorphic rocks, and crystallizing from melted material is another form of igneous rock formation.