Metamorphic rocks are formed when heat and pressure are applied to rocks in Earth's crust, causing them to change without melting.
(Metamorphic rocks; are formed; T:when heat and pressure are applied to rocks in Earth's crust) (heat and pressure; are applied; to rocks in Earth's crust)
Metamorphic rocks heat and pressure
are formed are applied
T:when heat and pressure are applied to rocks in Earth's crust
to rocks in Earth's crust