people in society are engaged in various economic activities.Some produce goods whereas some produce services.In order to understand these activities people are divided into groups.These groups are called sectors or activity.

1.Primary sector

(a).Those occupations which are closely related to man's natural environment.hunting,fishing,lumbering,animal rearing,farming and mining are important example of primary activity.
(b). This sector is also Called agricultural and related sector.
(c). primary products are the base for all other products that we subsequently make.

2.Secondary sector

(a).The occupation which produce finish goods by using the product of primary activity as raw materials included in secondary activity.e.g. manufacturing of cloth from cotter,sugar from sugarcane and steel from iron ore etc.
(b). This sector is related to industries and hence can be called industrial sector.
(c). the product is not produced by nature.

3.Tertiary sector

(a).These are activities that help in the development of primary and secondary sector.
(b).These activities by themselves do not produce good but they are an aid ora support for the production process.
(c). Since these activities generates services rather than goods.They are called service sector.e.g. Transport,storage,communication,banking etc.

Intermediate Goods:-those goods which are sold by one firm to another for resale or for further processing.

Final Goods:-they have crossed the boundary line of production and are ready for use by the final users. e.g.cloth,pen,coolers,etc.

Double counting:-The counting of the value of a product more than the once is called double counting.   

Gross Domestic Product:- It is the market value of the final goods and service produced within the country during one year.

Disguised unemployment:-It is the situation in which more workers are working in an activity than required.

Public Sector:-It is the sector which is controlled,managed and owned by the government.

Private Sector:-It is owned,controlled and managed by the individual or by a group of individuals.