Which shows the correct order of steps in the formation of coal? layers of dead plants pile up → plant matter is buried by rocks and dirt → dead plants fall in swamp → plant matter is compressed and is exposed to heat → coal forms plant matter is compressed and is exposed to heat → dead plants fall in swamp → layers of dead plants pile up → plant matter is buried by rocks and dirt → coal forms plant matter is buried by rocks and dirt → dead plants fall in swamp → layers of dead plants pile up → plant matter is compressed and is exposed to heat → coal forms dead plants fall in swamp → layers of dead plants pile up → plant matter is buried by rocks and dirt → plant matter is compressed and is exposed to heat → coal forms