Here's why:

* Sedimentary rocks are formed from the accumulation and cementation of sediments.

* Metamorphic rocks are formed when existing rocks (including sedimentary rocks) are transformed by heat and pressure.

The heat and pressure cause the minerals within the sedimentary rock to recrystallize and change their texture, resulting in a new metamorphic rock.

Example: Limestone (sedimentary rock) can be transformed into marble (metamorphic rock) under intense heat and pressure.