Why is mitochondria absent in red blood cells?
RBCs /(Red blood cells) need to remove cell structures like their nucleus, mitochondria, ribosomes upon maturity in order to carry oxygen very efficiently to the cells, utilising space vacant by these cell structures.
So, mitochondria is not absent in red blood cells from starting but yes on maturity it is removed to leave space for oxygen transportation which is the main function of red blood cells.