Which organs are hemopoietic in fetal life but not in adulthood?

During fetal development, hematopoiesis, or blood cell formation, occurs primarily in specific organs. The liver and the spleen are crucial sites for this process during fetal life. The liver is the first organ to begin hematopoiesis, starting as early as the 6th week of gestation, and it supports blood cell production throughout much of fetal development. The spleen also plays a significant role in the production of blood cells, particularly leukocytes, until the bone marrow takes over this function.

In adulthood, however, the liver and spleen diminish in their roles in hemopoiesis. The primary organ responsible for blood cell formation in adults is the bone marrow. As development progresses, hematopoiesis shifts from these embryonic organs to the bone marrow, which becomes the dominant site for the production of red blood cells, white blood cells, and platelets after birth. By adulthood, the liver and spleen are not involved in hemopoiesis, indicating their transition into other roles, primarily related to metabolism and immune functions, respectively.

Thus, the correct answer identifies the liver and spleen as organs that are hemopoietic during fetal life but lose that function in adulthood.