<Li> Migration occurs because individuals search for food, sex and security outside their usual habitation . Idyorough is of the view that towns and cities are a creation of the human struggle to obtain food, sex and security . To produce food, security and reproduction, human beings must, out of necessity, move out of their usual habitation and enter into indispensable social relationships that are cooperative or antagonistic . Human beings also develop the tools and equipment to enable them to interact with nature to produce the desired food and security . The improved relationship (cooperative relationships) among human beings and improved technology further conditioned by the push and pull factors all interact together to cause or bring about migration and higher concentration of individuals into towns and cities . The higher the technology of production of food and security and the higher the cooperative relationship among human beings in the production of food and security and in the reproduction of the human species, the higher would be the push and pull factors in the migration and concentration of human beings in towns and cities . Countryside, towns and cities do not just exist but they do so to meet the human basic needs of food, security and the reproduction of the human species . Therefore, migration occurs because individuals search for food, sex and security outside their usual habitation . Social services in the towns and cities are provided to meet these basic needs for human survival and pleasure . </Li> <Li> Zipf's inverse distance law (1956) </Li> <Li> Gravity model of migration and the friction of distance </Li> <Li> Radiation law for human mobility </Li>

Describe two general disadvantages of long distance migration