metamorphic rocks: Rocks formed when igneous or sedimentary rocks are modified by heat, pressure, or chemical reactions.
(Rocks; formed; T:when igneous or sedimentary rocks are modified by heat, pressure, or chemical reactions) (igneous or sedimentary rocks; are modified; by heat, pressure, or chemical reactions)
Rocks igneous or sedimentary rocks
formed are modified
T:when igneous or sedimentary rocks are modified by heat, pressure, or chemical reactions
by heat, pressure, or chemical reactions