depending on the price of the request (the person who buys) and the offer price (the person selling). In the practical language is supply and demand.

In principle, Bitcoin's pricing is the same as setting the price of oranges. There must be a deal between the offer price (the price of the people who sell Bitcoin) and the demand price (the person who buys Bitcoin).

Bitcoin is not controlled by any entity, since the characteristics of Bitcoin are interoperable.