The major reason which necessitates the expansion of agriculture is the increase in population. As more people are born and as medical advancements increase the lifespan of individuals, the number of people who need food also increases. Agriculture is the primary source of food production, and expanding agricultural practices is necessary to keep up with the growing demand for food. With more people to feed, there is a greater need for more land to be cultivated and for more crops to be grown. While factors such as rainfalls, manpower, and animal power can also play a role in agricultural expansion, population growth is the primary driving force behind the need to expand agriculture.