Earth is the only known planet that contains the necessary elements and life sustaining environment for life, as we know it, to flourish
No, there is no oxygen on any other planet other than Earth because there is no planet life on the other planets.
It is a dwarf planet. It is smaller than the other planets.
If you mean in a year, then it's because it takes different times to circle the sun then planet earth (because they are more far away or closer).
It is Neptune because the other "planets" are dwarf planets
its not a planet.....
Venus because they both have no moons
A star is a completely different thing from a planet. In other words no star is a planet.
Pluto is different because it is the only planet with an unusual orbit, instead of a regular circle orbit. It is also so much smaller than the other planets so we now call it a dwarf planet, not a real planet.Sources: my brain :P
Neptune
Because (as far as we currently know) Earth is the only planet in our solar system that supports life.
Pluto is a dwarf planet. It is smaller than the other planets. It also has a very irregular orbit.
because it is way to small for the other planets