Answer:
Used left or right I get to travel over cobblestone or gravel. Used up I vie for sweet success used down I cause men great duress.
I come without being fetched at night hides away as soon as daylight strikes. Although I may look small I am much mightier than what you can imagine.
I carry you down a gentle stream.
I march before armies, a thousand salute me. My fall can bring victory, but no one would shoot me. What am I?
The last man on Earth received a phone call, who was the caller?
It has no top or bottom, but it can hold flesh, bones, and blood all at the same time.