The ratio between the economically active and economically inactive of population is termed as dependency ratio.

Population composition refers to the characteristics such as age, sex, marital status, caste, religion, language, education, occupation etc

(i) Population census is the total process of collecting, compiling, analysing or other wise disseminating demographic, economic and social data pertaining, at a specific time, of all persons in a country or a well-defined part of a country.
(ii) The data collected through the census are used for administration, planning, policy making as well as management and evaluation of various programmes by the government.

(i) The uneven distribution of population in the country is the result of several factors such as physical, socio-economic and historical ones.
(ii) The physical factors include relief, climate, water, natural vegetation, minerals and energy resources.
(iii) Socio-economic factors consists of the religion, culture, political issues, economy, human settlements, transport network, industrialization, urbanization, employment opportunity etc.

The total number of people residing in a country at a specified period of time is called the 'Population' of that country