Answer:
This only turns over once you have travelled very far. What is it?
What is weightless but takes two people to hold it?
A reaction to being spooked that takes its name from waterfowl
I build up castles. I tear down mountains. I make some men blind. I help others to see.
What has roots as nobody sees, is taller than trees. Up, up it goes, and yet never grows?
You use it between your head and your toes, the more it works the thinner it grows.