Any material which can be transformed in a way that it becomes more valuable and useful, can be termed a resource. Thus land, water, minerals, forests, wildlife as well as human beings are resources. Some resources are likely to get exhausted soon, whereas others would last for a long period. Thus depending upon the availability of resources, during our continuous use, a resource may be renewable, non-renewable or cyclic. Resources which can renewed along with their exploitation are always available for use. Hence they are called renewable resources. For instance, forests are renewable. Non-renewable resources are such resources, if exploited at large scale they will deplete fast.