Standard trivia rules... If you get the answer correct, you choose the next question. If you don't post a question within a day or two, someone else can carry the thread on so the trivia keeps going as long as interest exists. I know that nothing can be done to actually prevent this, but don't resort to Google, it's easy to look this stuff up and it's pointless to do that.
A Wise Old Man once said.... Ask Grae_Face Arbiter's Live forever, SeeD's however never die.™ Why win? Why lose? Its nature, accept it children. “Wise men don't need to prove their point; men who need to prove their point aren't wise.” Become an Arbiter Today!
I'm assuming that you are talking about planets there and so I'm going to take a stab in the dark and say because all the planets are basically on a flat plane