Answer:
I go around in circles, but always straight ahead. Never complain, no matter where I am led. What am I?
What is the edge of earth and bread?
I only exist when you are here. Where you never were I can never be.
I am the signature stroll of ducks and penguins
I tremble at each breath of air, and yet can heaviest burdens bear. What am I?
Though not a plant, has leaves. Though not a beast, has spine. Though many wouldn't need this thing, It's more valuable than wine.