Answer:
Upon me you can tread, though softly under cover. And I will take you places, that you have yet to discover. I'm high, and I'm low, though flat in the middle. And though a joy to the children, adults think of me little.
Where do you go in through one hole and come out through two holes at the same time?
I can be quick and then I'm deadly, I am a rock, shell and bone medley. If I was made into a man, I'd make people dream, I gather in my millions By ocean, sea and stream.
I am what remains when nothing is left.What am I?
The sharp slim blade, that cuts the wind.
They are many and one, they wave and they drum, Used to cover a state, they go with you everywhere.