The document discusses several topics related to population, including distribution factors, dependency ratios, natural population growth rates, total population growth, fertility factors, migration types, causes of migration, and the negative effects of low population density. It notes that population distribution is influenced by resources like water and soils as well as communications and economy. Dependency ratios measure the percentage of a population that is working versus dependent. Natural growth comes from births minus deaths, while total growth includes that plus immigration minus emigration. Fertility is impacted by things like marriage age, family philosophies, and economic factors. Migration includes both temporary and permanent internal or international movement. Low population density can lead to underdevelopment and an inability to support industry or infrastructure.