Which feature is defined as magma that intrudes and crystallizes below the surface and may later be exposed?

• A. Dike
• B. Fault
• C. Pluton
• D. Sedimentary rock

Answer: (C)

When magma crystallizes below the surface, it forms an intrusive igneous body. A pluton is a substantial, typically irregular mass of solidified magma that cools underground and can be exposed at the surface later through uplift and erosion. This fits the description of magma intruding and crystallizing beneath the surface with the possibility of eventual exposure as a visible rock mass, like granite. In contrast, a dike is a narrow sheet that cuts through surrounding rocks, not a large underground body; a fault is a fracture along which rocks have moved, not crystallized magma; and sedimentary rock forms from deposited sediments, not cooling magma. So the best term for magma that intrudes and crystallizes underground and may later be exposed is a pluton.