Final answer:
Red blood cells lack nuclei at maturity and contain hemoglobin while white blood cells have nuclei and are involved in the immune response.
Step-by-step explanation:
In red blood cells, the nuclei are ejected as the cells mature, so mature red blood cells do not contain nuclei. They heavily rely on hemoglobin, a molecule that transports oxygen throughout the body. On the other hand, white blood cells do have nuclei and they are involved in the immune response to identify and target pathogens.