Answer:
If a man carried my burden, he would break his back. I am not big but leave silver in my tracks. What am I?
I have three feet but no arms or legs
I am the same written forward backward and upside down.
What can you break even if you never touch it?
Without a bridle, or a saddle, across a thing I ride a-straddle. And those I ride, by help of me, though almost blind, are made to see. What am I?
It has no top or bottom, but it can hold flesh, bones, and blood all at the same time.