They are used frequently but their usefulness is widely debated. Intelligence tests were developed by Alfred Binet, a French psychologist, in 1904. They do measure the ability to solve certain problems, but do not measure the ability to acquire new ideas or new behavior and adapt it to fit other situations. Most psychologists agree that the latter is intelligence. Thus, IQ tests may have limited usefulness and may not provide an adequate means to predict the likelihood of a student doing well or poorly in school.
Few communities are self-sufficient.
Residents in communities in areas with rich farm land may devote their time to market gardening. Down the road in an industrialized area, residents may not have land to raise gardens. As a result, they depend on each other for goods and services. A system of interdependence results, based in free exchange. When one crop is scarce, residents may grow more of another crop to satisfy the demand.