The distribution of population is influenced by several factors, including natural, social, economic, and demographic elements. Among the given options, the physiographic factor has a direct impact on population distribution. Physiographic factors include landforms, climate, water bodies, and soil conditions, which determine the suitability of an area for human settlement. Regions with favorable terrain and resources attract more people, while harsh environments such as mountains and deserts have lower population densities. Other factors like sex ratio, literacy, and life expectancy influence population characteristics but do not directly determine distribution.