It is the planet we live on
One unique fact about Maryland is that the largest fish ever caught weighed 200 pounds and 21 oz.
It starts with the letter D.
There are several unique facts about Pennsylvania. One unique fact is the very first computer was used in Pennsylvania.
something unique, the only one on Earth
It covers 60% of the Earth!
The Fact that there is only one shape like it.
the temperture varies
there is oxygen. if that counts for the surface :]
Life. One reason for this is the fact that it has water and a breathable atmosphere.
Yes. In fact, if they are not the same plane, then they must intersect in a unique straight line.
What is unique is that it has beings who ask questions starting, 'what is unique about . . . ?'
they have two valence electrons