Regional variations and population growth patternsThe demographic transition model provides an overview of the transformation or transition that occurs in several stages as the industrialization of a country advances . Using the demographic transition as a model, regional variations and population growth patterns can be described globally. The demographic transition model includes four stages: pre-industrialized society, agricultural revolution, industrial revolution, and post-industrial/developed societies. The first stage of the demographic transition model is the pre-industrial stage. At this stage, birth and death rates are generally high, which normally leads to almost no population growth in a country. The second stage of the demographic transition model is the agricultural revolution stage, where we see a reduction in death rates (DR), but birth rates (BR) remain high. At this stage, we also see a population explosion, which occurs mainly in underdeveloped and developing countries. Moving to the third stage, known as the industrial revolution, we see a radical change in population. Part of this change is due to advances in medicine and improved diets. These changes caused death rates and birth rates to decline. “Human life expectancy in industrialized countries has increased from an average of 35 years in the 18th century to 75 years or more today. "At this point we see that birth rates are about the same and death rates are lower. The final stage known as the post-industrial period produces zero population growth. Zero population growth is achieved when there is both a halt or decline in birth rates and death rates. However, many countries do not go through the demographic transition completely, but rather experience a prolonged period during the second stage, where the population explosion is in full effect, which poses some problems in countries and populations at scale. worldwide. regional variations and population growth patterns involve many elements. Fertility rates and death rates are good indicators of world population and patterns of growth and change. The total fertility rate (TFR) is the best forecast of a population over time. When we look at these numbers, we can begin to wonder what factors influenced these observed trends and variations..