What process is used to form metamorphic rocks?
A. Lava cools and hardens to form a rock.
B. Bits of sand and gravel form layers that turn into rock from pressure.
C. Extreme heat and pressure from inside the Earth turn rocks into new rocks.
D. None of the above
Answer: C. Extreme heat and pressure from inside the Earth turn rocks into new rocks.
Metamorphic rocks are form when rocks are subjected to high heat, high pressure, hot mineral-rich fluids or, more commonly, some combination of these factors.
