| Crdts. Teor. | 4 | In our daily life we often see natural phenomena that are both a wonder and a mystery. Sometimes we visit natural protected areas that are fascinating and we ask ourselves questions, which often have a complex answer. This subject is a basic overview of how living matter shows itself through Nature, and highlights the origin and intuitive explanations of those changes, mostly cyclical, to which substances that make our planet are subject to. It also draws attention to the deterioration that substances suffer as a consequence of the exploitation carried out by human beings. |