Final answer:
Gwen's feeling of satisfaction and belief that she has lived meaningfully suggest that she has achieved a sense of integrity, in line with Erikson's late adulthood stage of integrity versus despair.
Step-by-step explanation:
Gwen's satisfaction with her life and feeling that she has lived with meaning and done her best in the face of life's circumstances aligns with the concept of integrity in Erik Erikson's theory of psychosocial development. In late adulthood, the psychosocial challenge outlined by Erikson is integrity versus despair, where individuals reflect on their life's achievements and failures. Those who feel proud and content, like Gwen, have successfully achieved a sense of integrity, allowing them to look back on their lives with few regrets. On the other hand, those who fail to achieve this may experience despair, focusing on missed opportunities and unachieved goals. Thus, in the context of Erikson's stages of development, Gwen has developed a sense of integrity.