Which type of rock forms when molten rock cools and solidifies?

Which type of rock forms when molten rock cools and solidifies?

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

Answer: (D)

When molten rock cools and solidifies, it becomes igneous rock. This can happen either beneath the surface as magma that cools slowly, forming coarse crystals like granite, or on the surface as lava that erupts and rapidly cools, forming fine-grained rocks like basalt or rhyolite, or even glassy rocks like obsidian when cooling is very fast. This distinguishes igneous rocks from sedimentary rocks, which form from the deposition and cementing of sediments (such as limestone, which comes from accumulated shells and chemical precipitation), and metamorphic rocks, which arise when existing rocks are transformed by heat and pressure without melting. So the correct concept is that cooling and solidification of molten material produces igneous rock.

When molten rock cools and solidifies, it becomes igneous rock. This can happen either beneath the surface as magma that cools slowly, forming coarse crystals like granite, or on the surface as lava that erupts and rapidly cools, forming fine-grained rocks like basalt or rhyolite, or even glassy rocks like obsidian when cooling is very fast. This distinguishes igneous rocks from sedimentary rocks, which form from the deposition and cementing of sediments (such as limestone, which comes from accumulated shells and chemical precipitation), and metamorphic rocks, which arise when existing rocks are transformed by heat and pressure without melting. So the correct concept is that cooling and solidification of molten material produces igneous rock.