1. The Makeup of Societies

2. Social Stratification
Social stratification is a kind of social differentiation whereby a society groups people into socioeconomic strata, based upon their occupation and income, wealth and social status, or derived power (social and political). As such, stratification is the relative social position of persons within a social group, category, geographic region, or social unit.
In modern Western societies, social stratification typically is distinguished as three social classes: (i) the upper class, (ii) the middle class, and (iii) the lower class; in turn, each class can be subdivided into strata, e.g. the upper-stratum, the middle-stratum, and the lower stratum.[1] Moreover, a social stratum can be formed upon the bases of kinship, clan, tribe or caste, or all four.
Social Stratification

3. A race is a grouping of humans based on shared physical or social qualities into categories generally viewed as distinct by society.  First used to refer to speakers of a common language and then to denote national affiliations, by the 17th century the term race began to refer to physical (phenotypical) traits. Modern scholarship regards race as a social construct, that is, a symbolic identity created to establish some cultural meaning. While partially based on physical similarities within groups, race is not an inherent physical or biological quality.
Race

4. An ethnic group or an ethnicity, is a category of people who identify with each other based on similarities such as common ancestry, language, history, society, culture or nation.
Ethnicity is usually an inherited status based on the society in which one lives. Membership of an ethnic group tends to be defined by a shared cultural heritage, ancestry, origin myth, history, homeland, language or dialect, symbolic systems such as religion, mythology and ritual, cuisine, dressing style, art or physical appearance.
Ethnicity

5. Social mobility is defined as the movement of individuals, families, households, or other categories of people within or between layers or tiers in an open system of social stratification. Open stratification systems are those in which at least some value is given to achieved status characteristics in a society. The movement can be in a downward or upward direction.
Social Mobility