What is the rock cycle?

• A. A model that describes how rocks change between igneous, sedimentary, and metamorphic forms through processes like cooling, weathering, and heat/pressure.
• B. The sequence by which rocks are randomly formed.
• C. A cycle describing only sedimentary rock formation.
• D. A process that converts all rocks into soil.

Answer: (A)

Rocks are constantly transformed into other rocks through a connected set of processes, forming the rock cycle. Igneous rocks form when magma or lava cools and solidifies. Weathering and erosion break existing rocks into sediments, which are deposited and lithified into sedimentary rocks. Heat and pressure can alter any existing rock into metamorphic rocks, changing minerals and texture. If rocks melt again, they become magma and the cycle starts over as the molten material cools into new rock. This cycle shows how any rock type can become another over time and how surface processes link with deep Earth processes, often driven by plate tectonics. It isn’t about random rock formation, nor is it limited to sedimentary rocks, nor does it say that all rock becomes soil.