What Am I Riddles

Question: I fly and never rest. What am I?

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

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???