Which description best explains how sedimentary rocks form?

• A. From molten rock that cools and solidifies
• B. From fragments of other rocks that are deposited and cemented together
• C. From rocks altered by heat and pressure
• D. From chemical precipitation only

Answer: (B)

Sedimentary rocks form when pieces of other rocks and minerals are broken down, carried away by wind or water, and gradually settle in layers. Over time, these layers get buried, compacted, and cemented together by minerals in groundwater, turning loose sediment into solid rock. This deposition and cementation process is what makes sedimentary rocks distinct.

That’s why this description fits best: it emphasizes fragments being deposited and then cemented into rock. Other rock types come from different processes—igneous rocks form from molten rock that cools and hardens, and metamorphic rocks form when existing rocks are changed by heat and pressure. While some sedimentary rocks can form from chemical precipitation, the broader idea of sedimentary rock formation centers on deposition of fragments and their cementation.