Basically, it is the very gist of commodity pricing: supply and demand. When demand for oil rises in

Basically, it is the very gist of commodity pricing: supply and demand. When demand for oil rises in tandem with dwindling supply then prices are soaring.
Interest Rates
The second is also very relevant in the analysis of the foreign currencies, with this area being the interest rate factor. Such that when interest rates are increasing, then currencies appreciate because they offer foreign capitals, which desire to get more yields a very good destination to place their money.