Analysis of answer analysis questions: ear cells are highly differentiated cells, in which genes are selectively expressed; If it is cultured into an individual after nuclear transplantation, it is necessary to activate and re-express the closed gene, and C is correct. In the process of differentiation, cells will not lose genes, BD is wrong; The totipotency of differentiated cells is limited, and A is wrong.

Test center: this question examines the knowledge related to cell differentiation and totipotency, aiming at examining the key points of candidates' understanding of what they have learned.