Answer:
What grows in winter, dies in summer, and grows roots upward?
This only turns over once you have traveled very far. What is it?
Sometimes black, sometimes white, I have veins but no blood
It's like food but water kills it. What is it?
It happens when something has been cut with H2O.
Black we are and much admired. Many seek us if they are tired. We tire the horse, and comfort man, and turn White when we've fulfilled your plan.