MEGA Elementary Education Multi-Content Practice Test

What process is responsible for forming metamorphic rock?

1. Weathering sedimentary rock

2. Applying heat and pressure to igneous rock

3. Melting sedimentary rock

4. Cooling magma below Earth's surface

The correct answer is: Applying heat and pressure to igneous rock

Metamorphic rock forms primarily through the application of heat and pressure to existing rock types, particularly igneous, sedimentary, or even other metamorphic rocks. This process is known as metamorphism, which alters the mineral composition and structure of the rock without it melting. The intense conditions found deep within the Earth can cause changes such as recrystallization, foliation, or the development of new minerals, significantly transforming the parent rock into a metamorphic rock. Heat increases the energy within the rock's minerals, allowing for new bonds to form and existing bonds to break, while pressure can cause the minerals to realign. Together, these conditions create the distinctive textures and features that characterize metamorphic rocks, such as schist or gneiss. Other processes mentioned in the options, such as weathering, melting, or cooling, are related to different types of rock formation and transformation, but they do not contribute directly to the metamorphic process. For instance, weathering breaks down rocks into sediment, while cooling magma forms igneous rocks, and melting sedimentary rock would turn it into magma rather than metamorphic rock.