Geoterms Chp. 15

the average age that a person in a given population can
expect to live to.it varies from one country to another.

the average number of children a woman in a given
population will have in her lifetime. This number is different in
different countries.

the total fertility rate needed for a population to replace
itself. This number varies by country, but is about 2.1 in most
developed countries.

the study of human populations, including how they change due to births, deaths, aging, and migration

the number of old and young dependents who don’t work compared with the working-age population. The higher the ratio, the more young and old people the workers have to support.