Final answer:
The most active sites of hematopoiesis in adults are the sternum, ileum, and femur (option c), where red marrow is present and responsible for the production of blood cells.
Step-by-step explanation:
The most active sites of hematopoiesis in our body, which is the production of blood cells, are located in specific bones where red marrow is present. The answer to the student's question is option (c): sternum, ileum, and femur.
During adulthood, red marrow is primarily found in flat bones such as the sternum, as well as the pelvis, vertebrae, and the proximal epiphyses of long bones like the femur. In children, hematopoiesis can also occur in the medullary cavity of long bones. However, for adults, sites like ganglia and thorax do not participate in active hematopoiesis.
All formed elements of blood, which include erythrocytes (red blood cells), leukocytes (white blood cells), and thrombocytes (platelets), are derived from hematopoietic stem cells within the red bone marrow. Billions of these cells are produced daily to replace those that have a very brief lifespan.