Final answer:
In sociology, the level at which the majority population starts to leave when a minority group encroaches is called the 'tipping point'. A minority group is defined primarily by its lack of power, and polarization refers to the division between two extremes, which can lead to social fragmentation and expulsion.
Step-by-step explanation:
If a minority group invades charter-group territory, there is a tipping point, or level, at which a rapid massive exodus of the majority population will occur. This concept is often discussed in sociology and relates to the dynamics of intergroup relations and the impact of demographic shifts on social structures.
The tipping point is reached when the presence of the minority group becomes sufficiently large to trigger majority group members to leave an area, which can sometimes lead to various forms of expulsion or separatist movements. The one defining feature of a minority group is typically their lack of power. Numerical size may matter, but it is the dearth of power that characterizes a group's minority status more than numbers alone.
Such groups may face significant challenges including assimilation, segregation, and, in extreme cases, persecution and expulsion. Polarization is a challenge occurring when people or groups are divided between two extreme positions or ideologies, driving a wedge in society and often making constructive dialogue and compromise difficult.