A man tries to live where he is most comfortable. The reasons affecting the population density of people are the proximity of the river or other sources of drinking water, climatic conditions suitable for life, the presence of vegetation and animals, the availability of jobs and more.
First of all, climatic conditions. The more favorable they are, the better for life, and therefore there the population density will be higher and vice versa. In the modern world, economic stability is exerting an increasing influence, that is, in general, the development of the country.
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.