All subgroups and quotient groups of cyclic groups are cyclic. Smaller, stable subgroups exist within larger groups. Stratification is the process of dividing members of the population into homogeneous subgroups before sampling. Ethnic distinctions among the Mongol subgroups are relatively minor. The Germans included many quite distinct subgroups with differing religious and cultural values. The Germanic Saxons were divided into four subgroups in four regions. The Norse group may itself consist of several smaller subgroups. The very large rhodopsin A group has been further subdivided into 19 subgroups (A1-A19). In some cases, investigators are interested in research questions specific to subgroups of the population. An individual may be described as belonging to several subgroups. The pattern of Nuer scarification varies within specific subgroups. These styles may be divided into several special subgroups, such as counter puncher, etc. Various ways of selecting the sequence subgroups and objective function are reviewed in. FeLV is categorized into four subgroups. The Brahmanic group was enlarged by incorporating local subgroups, such as local priests.