Answer:
I am a nut with a hole
I am a little piece of paper, yet sometimes hold lots of value. I am all you need to get into big events, but will cost you. I am an important part of travel. And if lost, you're not coming. What am I?
Take off my skin I won't cry but you will.
Of the king I am blue and of the peasant I am red. Of the frog I am cold and of the dog I am hot instead. What am I?
The more you look at me The less you see.
It flows out of the soil, It burns you if it boils, And holds us in its coils, More valuable than gold, As black as it is old.