Which of these organs is not part of the immune system?

Of these, it’s the white bone marrow. If there had been red bone marrow, all the organs mentioned would be part of the immune system because the red bone marrow is the place of formation of the blood cells, i.e. also the leukos. Red bone marrow is located only in the bones (ribs, pelvic bones) and the growth zones (epiphyses). The tube bones, such as thighs, contain the white bone marrow, which is made of fatty tissue and has mainly storage function. If you buy a leg pane for soup cooking or awning, the white bone marrow is the galley part inside.