What is the highest level of the affective domain that requires the development of one's own value system?

The highest level of the affective domain that requires the development of one's own value system is characterizing. This level involves not just the acceptance of values but the integration of those values into one's personal philosophy and behavior. At this stage, individuals demonstrate internalization of values, leading to a consistent application in various situations. They actively live out their values in a way that reflects a deeper understanding and commitment.

In contrast, some of the other options represent earlier stages of the affective domain. Valuing involves expressing a value or belief but does not necessarily require the individual to fully embody or integrate those values into their identity. Organizing refers to the ability to bring together different values or ideas and prioritize them, indicating a level of complexity in one's value system but still not at the highest level of internalization. Responding involves active participation or engagement with values, such as showing enthusiasm or a willingness to act, but stops short of developing a personal value system.

Therefore, characterizing stands out as the most advanced stage where a person's actions consistently reflect their deeply held values, signifying a high level of commitment and personal integrity regarding those values.