1 RBC lack antihen on its surface 2 RBC have life span of 120 days because of lack of telomerase enzyme 3 RBC are destroyed by our own immune system 4 RBC are killed by spleen attacker cells
3 rd option seems most appropriate as RBCs die after 120 days after been through wearing provided by the blood capillaries and lacking of nucleus, they dont have the property to self repair so the die