Answer:
Each morning I appear to lie at your feet, all day I follow no matter how fast you run. Yet I nearly perish in the midday sun.
My tongue hangs out as I run over fields and streets all day. I get tied up every morning and untied at night.
I build up castles. I tear down mountains. I make some men blind. I help others to see.
They're up near the sky, on something very tall. Sometimes they die, only then do they fall.
I'm not man's best friend, I'm their enemy, I can mark your end, yet you do not see me, I am very small, but very tough, If you have me, then you have it rough.
What an fill a room but takes up no space?
Difficult
Animal
Easy
Food
Funny
Kids
Logic
What am I?