Answer:
So simple, that I can only point. Yet I guide men all over the world.
I have three feet but I cannot walk. What am I?
I grow up while growing down
I'm a god a planet and a measurer of heat. Who am I?
I am always around you but often forgotten. I am pure and clean most of the time, but occasionally rotten. What am I?
Whoever made me don't want me. Whoever bought me don't need me. Whoever use me don't know me.