Answer:
Minerals rearrange into layers within a metamorphic rock because they are forced by a pressure force and a very high temperature.
Explanation:
During the metamorphism process the minerals must be stable under the high temperatures and pressure they receive.
This results in the generation of new minerals with different chemical composition.
All igneous, sedimentary or metaformic rocks can be transformed into a metamorphic rock if they receive enough heat and pressure necessary to be formed, changing their composition inside but without melting.
When the rocks are subjected to high pressures, flat plates are formed and that can result in foliation, which is formed when this pressure is exerted in a single direction.
They can also be non-foliated as are limestone and quartzite.
