Answer:
Three little letters, a paradox to some. The worse that it is, the better it becomes.
A hole leading in, a hole leading out, we connect to a cavern that is slimy all throughout. What are we?
Runs smoother than any rhyme, loves to fall but cannot climb.
It is a sound of empty, speak and it'll talk back plenty. But all the more you yack, you'll get the same words back.
What do you fill with empty hands?
This food is a tortilla filled with cheese and sometimes chicken before being heated or cooked.