Scientist assist rocks into three different types, they make this classification on the basis of their process of formation.
<u>EXPLANATION:</u>
The three classifications of rocks, scientists have given are sedimentary, igneous rocks and metamorphic.
The main difference between these rocks is the process of their formation.
The rocks that are formed from the sand particles are sedimentary rocks and that formed under the earth surface by metamorphosis process is metamorphic rock.