Shelly was surprised to learn the dwarf planet Pluto used to be considered a planet. What would have had to be true for Pluto to remain categorized as a planet?
Pluto would need to have an atmosphere.
Pluto would need to clear the neighborhood of its orbit.
Pluto would need to have a larger moon.
Pluto would need to have water or ice.
Pluto would need to have an atmosphere.
Pluto would need to clear the neighborhood of its orbit.
Pluto would need to have a larger moon.
Pluto would need to have water or ice.