Which of the following aspects of an audience is most affected by age?

The answer addressing which aspect of an audience is most affected by age is the stability of attitudes. Age can significantly influence an individual's attitudes and beliefs, primarily due to generational experiences and the differing historical contexts in which people grow up. Younger audiences may be more open to change and new ideas, while older audiences may have more stable, entrenched beliefs shaped by the experiences and norms of their earlier years.

As people age, their experiences, socialization, and maturation contribute to how stable or changeable their attitudes become. This can impact how they respond to messages, speakers, and topics. For example, an older audience may be more resistant to new trends or ideas that contradict their long-held beliefs, while a younger demographic might exhibit more fluidity in their attitudes due to exposure to diverse perspectives and rapid societal changes.

In contrast, while cultural interests, educational level, and ethnic identity can also be influenced by age, these factors are more complex and impacted by a variety of societal and individual elements beyond just the passage of time. Thus, the stability of attitudes is most closely correlated with the influences of age.