First of all excuse me if you think its a noob question, but consider me a noob as I am trying to understand.
I've got a couple of questions about mining, (which I think fits in bitcoin section rather than the mining section)
First: Why do bitcoin needs mining?
Second: What do they actually mine?
In my opinion here is my answers:
First: Bitcoin needs mining to have a supply for the market and to supply the demand of the buyers or investors in the different kind of exchange and have a complete circulation of bitcoin.
Second: They mine bitcoin because they find it profitable by mining bitcoin 24/7 and also for confirming different kind of transactions online.