The complete sentence is this:
From the standpoint of geography and demography, a POPULATION consist of people who live in a particular area.
In geography, population refers to the total amount of people, who are living in a particular area or a well defined specific location. Populations usually differ in size, structure, composition and distribution. The factors that determine whether a population will increase or decrease include birth rate, death rate, emigration, immigration, etc. Demography refers to the study of human populations and its characteristics.