In RBC there is no nucleus then why it is considered as living and from where the metabolism of the RBC is controlled ?
Due to the presence of pre-formed metabolic enzymes, they are considered as living cell. The absence of a nucleus is an adaptation of the red blood cell for its role. It allows the red blood cell to contain more haemoglobin and, therefore, carry more oxygen molecules. It also allows the cell to have its distinctive bi-concave shape which aids diffusion.