Any organic material used by humans can be considered as a natural resource. Natural resources include oil, coal, natural gas, metals, stone, and sand. Air, sunlight, soil, and water are other natural resources.
The objects or group of objects that have been widely agreed upon to be used a s form of exchange is called currency. The currency is a very useful method for exchanging things, and it has been widely accepted around the world, with some currencies being globally accepted, while some only regionally, or locally.
The reason why the currencies have been introduced is so that the two or more sides in the process of exchange have the same means and valuations, thus making the exchange very easy. Some of the strongest currencies in the world are the American Dollar, Euro, British Pound, Swiss Frank...
According to the law of superposition, the sediments are usually deposited on top of one another, giving rise to the formation of sedimentary layers. In an undisturbed sedimentary sequence, the layers that are formed at the apical portion are the youngest and the layers that are found at the base are the oldest.
Thus, the concept of laying down of sediments on top of one another is the law of Superposition.
