As countries grow, the primary sector gets smaller and the secondary and tertiary sectors grow.
DEVELOPED COUNTRIES are countries where manufacturing is imported or conducted with high living standards.
Developed countries have improved living standards, increased freedom, high income and investments and are mostly employed in the tertiary sector.
DEVELOPING COUNTRIES are countries that have low income and investments compared to developed countries, low levels of education, poor housing and a high number of workers employed in the primary sector.
Some countries in between developed and developing countries are called progressing countries.
Developed countries that mainly work in the tertiary sector have some disadvantages as they will depend on the developing countries to provide them with basic needs.
Eventually when these developing countries will progress it'll have a negative impact on developed countries as they will no longer have people working in the primary sector.