Primary occupations :

• Primary occupations are directly dependent on nature.
• The products of primary occupations serve as raw material for secondary occupations.
• Primary occupations require comparatively lesser amount of skills and capital investment. Therefore, generally primary occupations are associated with developing countries
• Generally, fewer skills are required to perform primary occupations such as animal husbandry, fishing, lumbering, etc. Therefore people engaged in these occupations get comparatively less income.

Secondary occupations :

• In secondary occupations, the raw material obtained from primary occupations is processed producing finished goods.
• In these occupations, more durable goods are produced and their quality is enhanced.
• Examples : Shrikhand, butter, cheese, etc. are processed from milk. Sugar is processed from sugarcane, etc.

Tertiary occupations :

• Occupations providing complementary services to the primary and secondary occupations are called tertiary occupations.
• Tertiary occupations require comparatively more amount of skills and capital investment. Therefore, tertiary occupations are associated with developed countries.
• Examples : Transport of milk and milk products, loading and unloading of goods, sale of goods, etc.

Quaternary occupations :

• The special services rendered by people having some special skills /expertise are called quaternary occupations.
• Examples : Inspecting the quality of cheese, paneer, maintaining machines, designing buildings, treating patients, teaching, etc.
• People engaged in these occupations get comparatively high income.