Question

why the pluto planet called a dwarf planet

Answer 1

because it is far so much then we say that it's dwarf

Answer 2

It is called so because it is too small to be considered a planet.It doesn't even have a proper orbit. In 2006 scientists discovered two more dwarf planets out of which one was slightly bigger than Pluto but wasn't classified as a proper planet. Pluto was then classified as a dwarf planet and not as a planet.

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