I am unique

I am higher than the sky.
I am deeper than the sea.
I am an open book.
Yet, my mysteries, you can’t see.

I am the tip of the roots
And the highest limb of the tree.
I am the heat of the desert
And the water of the sea.

I am slower than the sloth.
Yet I am faster than the tiger.
I am soft as cotton balls.
Yet, I am the toughest fighter.

I am the spine of a person
And the knife which kills another.
I am just another you.
Yet, I am unique like no other.