Good Riddles

Question: I'm number three.
But I'm not a number.
I'm hot and cold at the same moment but not at the same time.
I'm number three.
But I'm not a number.

Who or what am I?

Question: You have a bag with 'N' strings in it. You randomly grab two ends and tie them together until there are no more loose ends.

In the end, what is the expected number of loops (strings tied to their own end)?

Question: What grows when you take from it?

Question: I am apart of everything, including you. Once I die, I will begin anew. As my life status becomes dire, I burn brighter and brighter. What am I?

Question: What has classes but moves?