Read the following passage carefully and answer the question given below

Population Geography, a sub field of Geography, studies spatial variations in distribution, composition, migration and growth of population to the terrain, in a way it involves demography in geographic perspective.

If focuses or questions such as where populations are found and how the size and composition of these populations in regulated by demographic processes of fertility, mortality and migration contributions to population geography are cross-disciplinary. Disciplines other than geography contributing to population geography include demography, sociology and economics.

Since its inception, population geography has taken at least three distinct forms. The earliest emerging in the 1950s, focused on the systematic study of population distribution as a whole and spatial variations in dynamic characteristics of population. Trewartha, Zelin sky, W.A.V Clark and other from U.S.A. and J.B Garnier and Pierre George in France Pioneered this phase.

Population geography has widered its scope to cover different variety of themes with time. It studies various population characteristics including gender, religion age, disability racrete by grouping population characteristics into political and administrative units. All such variables go far beyond the vital statistics of births, deaths and marriage /migrations.

Geographers have studied relations between demographic growth, displacement and access to resources at the International scale. Examples are density maps prepared using choropleth, isoline and dots.