Specialization ( specialisation) is the separation of tasks within a system. In a multicellular creature, cells are specialized for functions such as bone construction or oxygen transport. In capitalist societies, individual workers specialize for functions such as building construction or gasoline transport. In both cases, specialization enables the accomplishment of otherwise unattainable goals. It also reduces the ability of individuals to survive outside of the system containing all of the specialized components. Adam Smith described economic specialization in his classic work, The Wealth of Nations. Specialization is when people specialize in one thing or another which they are good at. One argument holds that the introduction of agriculture to tribes and hunter gatherer's enabled individuals to safely commit more Free Time and resources to maximize their effectiveness in one aspect for mutual benefit to the whole community. Whereas before, this "Free Time" was critically challenged with time spent securing food, shelter and companionship.