Final answer:
According to Erikson, the major developmental task for a person entering adolescence is to develop a unified sense of self.
Step-by-step explanation:
According to Erikson's theory of psychosocial development, the major developmental task for a person entering adolescence is to develop a unified sense of self. This is known as the stage of identity versus role confusion. During this stage, adolescents explore different identities and strive to define who they are and what they stand for. Successful resolution of this task leads to a strong sense of identity and the ability to remain true to oneself despite external influences and challenges.