Question

Is pluto the only dwarf planet?

Answer 1

No, Pluto isn't the only dwarf planet. There are officially five recognized dwarf planets in our solar system: Pluto, Eris, Haumea, Makemake, and Ceres.

Answer 2

Pluto orbits the Sun and is spherical in shape, but it has failed to get rid of other objects in its orbit, which intersects with Neptune. This is why Pluto is now considered a dwarf planet.