Families specialize in their tasks by dividing the work among the different members according to what they are best qualified to do。 For example， mothers cook， children wash dishes and make beds， fathers mow the grass and paint the house。 By doing the same thing again and again， and by close cooperation， a family is able to work faster and get more work done than if just one do many kinds of tasks。
Similarly， it is 'cooperation' that make our complicated modern society work。