Answer:
I am a box which holds keys but not locks. With the right combination, I may unlock your soul. What am I?
What force and strength cannot get through I with my unique teeth can do.
Travel a mile and I will change, travel a million and I will end as I started. What am I?
I begin and have no end. Eventually, I will be the ending of all that has begun. What am I?
I'm blue at day and black at night. I do contain some creatures born and died. What am I?
Black we are and much admired. Many seek us if they are tired. We tire the horse, and comfort man, and turn White when we've fulfilled your plan.