Usefulness is the most obvious difference between living and nonliving systems and is thus a specific product of biological evolution. It originates as a product of the natural selection. Organisms have these properties jointly with systems formed by the targeted activities of human beings. The properties of artificial systems created by humans are usually subservient to a particular target, a certain purpose. For example, the construction of a knife, its shape and material are dependent on its purpose – cutting, slicing or stabbing. It corresponds both to the properties of the human hand that will hold it and also to the properties of the material that it will slice or cut. Similarly, the individual organs of living organisms have a structure, shape and material that are dependent on the function that they perform. They are generally very well adapted to this function and to the conditions under which the organisms are found. Usefulness is not generally encountered in nonliving nature, and the properties of nonliving systems frequently reflect the causes and mechanisms of their formation but not any purpose or target.