Final answer:
Anna Freud is renowned for her pioneering work in child psychoanalysis and her contributions to ego psychology, building upon and expanding her father Sigmund Freud's theories.
Step-by-step explanation:
Anna Freud is primarily responsible for the study and development of child psychoanalysis and contributed significantly to ego psychology. She expanded her father, Sigmund Freud's theories, particularly in relation to the psychological development of children, and became an influential figure in the history of child psychology. Anna Freud's work is recognized for her development of the field of child psychoanalysis and her theoretical and clinical contributions to the understanding of child psychology. She is known for her work on defense mechanisms and for emphasizing the importance of the ego's role in psychological processes.