administrators and armed forces from the urban centers into rural hinterlands to raise taxes, recruit soldiers, and fortify buffer zones. European states consequently developed strong institutions and capital-periphery linkages. By contrast, geographic and climatic factors in pre-colonial Africa made establishing absolute control over particular pieces of land prohibitively costly. For example, because African farmers relied on rain-fed agriculture and consequently invested little in particular pieces of land, they could easily flee rulers rather than fight. Some early African empires, like the Ashanti Empire, successfully projected power over large distances by building roads. The largest pre-colonial polities arose in the Sudanian Savanna belt of West Africa because the horses and camels could transport armies over the terrain. In other areas, no centralized political organizations existed above the village level. African states did not develop more responsive institutions under colonial rule or post-independence. Colonial powers had little incentive to develop state institutions to protect their colonies against invasion, having divided up Africa at the Berlin Conference. The colonizers instead focused on exploiting natural resources and exploitation colonialism. The effect of disease environments Dr. Marcella Alsan argues the prevalence of the tsetse fly hampered early state formation in Africa. Because the tsetse virus was lethal to cows and horses, communities afflicted by the insect could not rely on the agricultural benefits provided by livestock. African communities were prevented from stockpiling agricultural surplus, working the land, or eating meat. Because the disease environment hindered the formation of farming communities, early African societies resembled small hunter-gatherer groups and not centralized states. The relative availability of livestock animals enabled European societies to form centralized institutions, develop advanced technologies, and create an agricultural network. They could rely on their livestock to reduce the need for manual labor. Livestock also diminished the comparative advantage of owning slaves. African societies relied on the use of rival tribesman as slave labor where the fly was prevalent, which impeded long-term societal cooperation. Alsan argues that her findings support the view of Kenneth Sokoloff and Stanley Engerman that factor endowments shape state institutions. Llamas, chuño and the Inca Empire Carl Troll has argued that the development of the Inca state in the central Andes was aided by conditions that allow for the elaboration of the staple food chuño. Chuño, which can be stored for long times, is made of potato dried at freezing temperatures that are common at nighttime in the southern