Answer:
I have a tongue, but do not talk. I follow close, but neither run nor walk. Coupled and hitched, but never married. You couldn't bear the load I've carried.
You need a key to receive an answer from me. The answer you'll find is straight from your mind. What is it?
With head without hair. With mouth without tooth.
Runs smoother than any rhyme, loves to fall but cannot climb.
You must keep this thing. Its loss will affect your brothers. For once yours is lost, it will soon be lost by others.
I have two eyes in the front and a lot of eyes on my tail
Difficult
Animal
Easy
Food
Funny
Kids
Logic
What am I?