For years Pluto was known as a planet. The coldest, smallest and furthest from the sun. In recent years, Pluto's status has changed and it is no longer a considered a planet. What evidence led to the status downgrade?
A)
The theory that Pluto is really a moon.
B)
Spacecraft discovery after landing on Pluto.
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Findings that suggest Pluto doesn't have a solid surface.
D)
Findings that Pluto's characteristics were very similar to small icy objects
beyond Neptune.