Metamorphic rocks are formed from pre-existing rocks (either igneous, sedimentary or metamorphic) which have been subjected to high heat and/or pressure.
(Metamorphic rocks; are formed; from pre-existing rocks) (Metamorphic rocks; from pre-existing; rocks (either igneous, sedimentary or metamorphic) which have been subjected to high heat and/or pressure) (rocks; have been subjected; to high heat and/or pressure)
Metamorphic rocks Metamorphic rocks rocks
are formed from pre-existing have been subjected
from pre-existing rocks
rocks (either igneous, sedimentary or metamorphic) which have been subjected to high heat and/or pressure
to high heat and/or pressure