The family is a social institution. The importance of the family in an individual"s life usually depends on the size of the society. In small, primitive (原始的，早期的) societies, the family is the dominant social institution in an individual"s life. In larger, more complex societies, other social institutions are created to meet the needs of an individual.
There are two basic family structures. The first structure is the extended family. The extended family includes all of an individual"s blood relatives, including spouse, children, parents, brothers and sisters, grandparents, cousins, and aunts and uncles. The nuclear family is limited to the basic family nucleus: father, mother, and children.
The extended family structure tends to exist in agricultural societies. In such societies family ties serve as a strong source of cultural and societal interaction. The nuclear family structure tends to exist in industrialized societies. In industrial societies, other social institutions (such as religion, education, and government) act as the primary sources of cultural and societal interaction. Based on the information in the passage, all of the following can be concluded about extended and nuclear family structures EXCEPT that ______.
A．the nuclear family generally is smaller than the extended family B．the family is more important in primitive societies than in industrialized societies C．the extended family structure can not survive in an industrial society D．the nuclear family generally is not as strong a source of cultural and societal interaction as the extended family