Anything, which is required or used to sustain life, is called a resource. A natural resource is the resource obtained from Nature.
Resources are all these requirements of organisms, populations and communities which help in accumulation of energy by their availability. Initially man identified these natural gifts when were available around him and learnt to use them. It is well known that everything that comes from nature has some utility for men but its utilization is only provided the availability of appropriate technology is known.
Sunshine, wind, forest and wild life were present much before the appearance of man on the earth. In a similar manner, for century's coal and mineral oil were present below the earth's surface but the appropriate technologies were not known to utilize them.
With the development of civilization and technology it has now been possible to use different kinds of energy. Thus, it can be said that any material may be termed as a resource provided appropriate technology is available to transform them into more valuable forms. Natural resources can be defined as things materials of nature, that can be put to some use by human beings for their growth, development, and other necessities are called as "Natural Sources".
For example, air, water, soil, forests, animals, minerals, metals, energy and other substances are some, examples of natural resources that are utilized by human beings. At present, total global production is nearly enough to match the human demand for energy, materials etc., if we judiciously distribute the resources available to us.
The resources are not equally distributed throughout the world. We can realize the value of resource only when it is rather scarce. Over exploitation threatens most of our natural resources now.