Answer:
What is full of holes but still holds water
I'm light as a feather, yet the strongest man can't hold me for more than 5 minutes.
A hill full, a hole full, yet you cannot catch a bowl full.
What is lighter than what it is made of?
An iron horse with a flaxen tail. The faster the horse runs, the shorter his tail becomes.
I have two bodies joined together as one. When standing still I run and run.