Rapid population growth occurs when the number of births exceeds the number of deaths in a population. This can be influenced by several factors, including improved medical care, which reduces the number of deaths, and an absence of natural hazards that can also cause death. Additionally, if family planning methods are not widely used, then there may be a higher number of births, which can contribute to rapid population growth. Therefore, the absence of factors that limit population growth, along with improvements in healthcare, can lead to a rapid increase in population.