Completar frases 3 FILL in the blank Versión en línea FILL In the blank please por Natalie Danee Hay 1 unless device involves residence Populations can change through three processes : fertility , mortality , and migration . Fertility involves the number of children that women have and is to be contrasted with fecundity ( a woman's childbearing potential ) . Mortality the causes , consequences and measurement of processes affecting death in a population . Demographers most commonly study mortality using the Life Table , a statistical which provides information about the mortality conditions ( most notably the life expectancy ) in the population . Migration refers to the movement of persons from an origin place to a destination place across some pre - defined political boundary . Migration researchers do not designate movements as migrations' they are somewhat permanent . Thus demographers do not consider tourists and travelers to be migrating . While demographers who study migration typically do so through census data on place of , indirect sources of data including tax forms and labor force surveys .