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 two eyes in the front and a lot of eyes on my tail. What am I?
I can be swallowed, but I can also swallow you. What am I?
Flat as a leaf, round as a ring; have two eyes, can't see a thing. What am I?
I tremble at each breath of air and yet can heaviest burdens bear.
What do you purposefully put lots of in and on your body, but run away from when you encounter it outside?