Neither: Eris is a dwarf planet in the kyper belt and is known as a KBO or Kyper belt object.
Inner.
inner planet
It is an inner planet.
Saturn is an outer planet. The outer and inner plantes are divided by the asteroid belt.
Venus is an inner planet
Venus is an inner planet.
outer planet
It's the outer planet.
Inner, cause there is a ring of asteroids between Mars and Jupiter so therefore that makes it an inner planet & not an outer planet.
Uranus is an outer planet.
Mars is an inner planet, located between Earth and the asteroid belt. The inner planets are rocky and terrestrial, while the outer planets are gas giants.