Natural resources and classification.

Man lives in nature the progress of mankind depends upon the exploitation of different natural resources. The intelligent utilization of soil, water, coal, electricity, oil, gas and nuclear energy is very important for the development of a nation. India posses the world’s largest resource of coal andthird and fourth largest resource of manganese and iron.The earth is facing an ecological crisis and is degrading her natural resourcesday by day, due to over exploitation. Man  utilise the resources for food, shelter and clothing are the primary requirements of man. Early humansociety has used naturalresources, relatively in much less quantity to cover their needs.
Natural resources
The natural resources are the components of lithosphere, hydrosphere and atmosphere and they include energy, air, water, soil, minerals, plant and animals. For humman resources are those materials and sources of energy which are needed for survival and comforts.
Types of natural resources
Natural resources are classified in different ways. i.e. on the basis of chemical composition, availability and distribution.
A. Natural resources are of three types on the basis of their chemical composition
1. Inorganic Resources:eg. air, water and minerals
2. Organic Resources    :eg. plants, animals. micro-organisms and fossil fuels.
3. Mixture of Inorganic and Organic Resources: eg. soil
B. Natural resources are of two types depending upon their availability and
abundance.
1. Inexhaustible Resources are not likely to be exhausted by man’s use. eg .air, clay, sand,
tidal energy etc. Although the air is available in exhaustible quantity, it can be
degraded, if its pollution is not checked.
2. Exhaustible Resources are likely to be exhausted by human use. They are further classified into two types renewable and non-renewable.
a. Renewable Resources have inherent capacity to reappear or replenish themselves by quick
recycling, reproduction and replacement within a reasonable time. eg.Soil and living organisms are the main renewable resources.
b. Non- Renewable Resources lack the ability for recycling and replacement. The substances with a very long recycling time are also regarded as non-renewable resource e.g. fossil fuels like coal, petroleum and natural gas and minerals.
Underground water, forests and wild life are regarded renewable resources but become non-renewable, if they are not used properly.