What Am I Riddles

Question: I have keys but no lock, you can enter but not leave what am I?

Question: I talk, but I do not speak my mind
I hear words, but I do not listen to thoughts
When I wake, all see me
When I sleep, all hear me
Many heads are on my shoulders
Many hands are at my feet
The strongest steel cannot break my visage
But the softest whisper can destroy me
The quietest whimper can be heard.

Question: Half of those who read this riddle, I am your best friend.
I depend on you, but it's you I will defend.

What am I?

Question: Black were are and much admired, Men seek for us if they are tired We tire the horse but comfort man, Tell me this riddle if you can.

Question: I am a thing, when I look at him , he looks at us!! who am I???