Which rock type forms from deposition and cementation of sediment?

• A. Igneous
• B. Metamorphic
• C. Extrusive rock
• D. Sedimentary

Answer: (D)

Sedimentary rocks form when sediment is deposited in layers and then becomes solid through compaction and cementation. Deposition lays down particles over time, and cementation uses minerals dissolved in water to glue those grains together, turning loose sediment into rock. This sequence is what distinguishes sedimentary rocks from other types, making it the right answer.

Igneous rocks come from cooling and solidifying molten rock, either below the surface (intrusive) or on the surface (extrusive). Metamorphic rocks arise when existing rocks are changed by heat and pressure, often with mineral transformations, without first forming from deposited sediment. Extrusive rocks are a type of igneous rock formed by rapid cooling at the surface, not by deposition and cementation.