Final answer:
Reticulocytes are indeed found in circulating blood and are filled with hemoglobin and some ribosomes.
Step-by-step explanation:
True. Reticulocytes are immature red blood cells that are found in the circulating blood. They contain hemoglobin and some ribosomes. Reticulocytes provide a rough estimate of the rate of red blood cell production. They typically make up about 1-2 percent of the total red blood cell count.