availability of fresh water, fertile soil, and temperate climate of different locations. As farming populations gathered in larger and denser communities, interactions between these different groups increased. This led to the development of governance within and between the communities. As communities got bigger the need for some form of governance increased, as all large societies without a government have struggled to function. Humans have evolved the ability to change affiliation with various social groups relatively easily, including previously strong political alliances, if doing so is seen as providing personal advantages. This cognitive flexibility allows individual humans to change their political ideologies, with those with higher flexibility less likely to support authoritarian and nationalistic stances. Governments create laws and policies that affect the citizens that they govern. There have been multiple forms of government throughout human history, each having various means of obtaining power and the ability to exert diverse controls on the population. As of 2017, more than half of all national governments are democracies, with 13% being autocracies and 28% containing elements of both. Many countries have formed international political organizations and alliances, the largest being the United Nations with 193 member states. Trade and economics Trade, the voluntary exchange of goods and services, is seen as a characteristic that differentiates humans from other animals and has been cited as a practice that gave Homo sapiens a major advantage over other hominids. Evidence suggests early H. sapiens made use of long-distance trade routes to exchange goods and ideas, leading to cultural explosions and providing additional food sources when hunting was sparse, while such trade networks did not exist for the now extinct Neanderthals. Early trade likely involved materials for creating tools like obsidian. The first truly international trade routes were around the spice trade through the Roman and medieval periods. Early human economies were more likely to be based around gift giving instead of a bartering system. Early money consisted of commodities; the oldest being in the form of cattle and the most widely used being cowrie shells. Money has since evolved into governmental issued coins, paper and electronic money. Human study of economics is a social science that looks at how societies distribute scarce resources among different people. There are massive inequalities in the division of wealth among humans; the eight richest humans are worth the same net monetary value as the poorest half of all the human