they get their energy from the sun
this have not been answered yet
planets can be classified according to the minerals that they consists and also according to the names of some of the greek mythlogy characters.
A Dwarf Planet because a few years ago scientists discovered 30 planet-like rocks that were the size of Pluto and didn't want to name 30 new planets so they labeled them AND Pluto as dwarf planets.
Active and passive.