What has six faces, but does not wear makeup, has twenty-one eyes, but cannot see?

How can you write nineteen in a manner that if we take out one, it becomes twenty?

I am weightless, but you can see me. Put me in a bucket, and I'll make it lighter. What am I?

What has to be broken before you can use it?

I am taken from a mine and shut up in a wooden case, from which I am never released, and yet I am used by almost every person. What am I?

How many letters are in the alphabet?

I make two people out of one. What am I?

I know a nine-letter word having only one vowel.
Do you ?

I look flat, but I am deep. Hidden realms I shelter. Lives I take, but the food I offer. At times I am beautiful. I can be calm, angry, and turbulent. I have no heart but offer pleasure as well as death. No man can own me, yet I encompass what all men must have. What am I?

In four steps you need to move the word 'cold' From 'warm' by replacing one alphabet at a time such that every word formed at each step is acceptable in English Dictionary.