Answer:
What is bought by the yard by is worn by the foot?
This thing runs but cannot walk, sometimes sings but never talks. Lacks arms, has hands; lacks a head but has a face.
What is the heart of many risks, has a heart, but is not a living being?
I am mother and father, but never birth or nurse. I'm rarely still, but I never wander.
What comes once in a minute, twice in a moment, but never in a thousand years?
You use it between your head and your toes, the more it works the thinner it grows.
Difficult
Animal
Easy
Food
Funny
Kids
Logic
What am I?