exposure to extreme heat and pressure changes sedimentary rock into metamorphic rock & if something changes into something else then that something else is formed from that something ->  metamorphic rock is formed from sedimentary rock  metamorphic rock is formed from sedimentary rock & the formation of metamorphic rock is a sequential process, with stages of rock being compacted, heated, recrystallized ->  metamorphic rock is formed from sedimentary rock being compacted, heated, and recrystallized  metamorphic rock is formed from sedimentary rock being compacted, heated, and recrystallized & limestone is a kind of sedimentary rock ->  metamorphic rock is formed from limestone being compacted, heated, and recrystallized  metamorphic rock is formed from limestone being compacted, heated, and recrystallized & marble is a kind of metamorphic rock -> marble is formed from limestone being compacted, heated, and recrystallized