Anything which is useful to man, or can be transformed into a useful product or can be used to produce a useful thing can be referred to as a Resource. A natural resource is the resource obtained from Nature. It is these natural resources which form the very basis of entire life on this planet. A natural resource can be of the following two types:
1. Biotic Resources.
2. Abiotic resources.
A biotic resource is the resource which is directly or indirectly derived from photosynthetic activity of green plants. Food fruits, wood, fiber, milk and milk products, fish meat, leather etc. are termed as biotic resource. Coal, oil and natural gas are also biotic resources as they were produced by photosynthetic activity of plants which occurred millions of years ago. Mineral material, fresh water, rocks, salts and chemicals etc. are termed as abiotic resources as biological activity is not involved in their formation.