Final answer:
Statewide representation is the characteristic of interest groups having members in all regions of the state, which helps them to represent diverse perspectives and influence state policy.
Step-by-step explanation:
The characteristic of some interest groups that refers to the fact that the groups have members in all regions of the state is known as Statewide representation. This quality ensures that the interest group represents a broad cross-section of individuals across different geographic areas within a state, lending diverse perspectives to the group’s objectives and potentially increasing its influence on state policy. Examples of such groups include membership organizations like the NRA and the Brady: United Against Gun Violence, both of which have a national scope but also seek to represent members at the state level.