Which of the following describes a significant symptom of bone marrow syndrome?

A significant symptom of bone marrow syndrome is a decrease in red blood cells (RBC). This condition arises as a consequence of exposure to high doses of ionizing radiation, which can damage the bone marrow—where blood cells are produced. As a result, the body is unable to manufacture enough healthy RBCs, leading to anemia, which is characterized by fatigue, weakness, and pale skin. The decrease in RBCs is particularly significant because it affects the oxygen-carrying capacity of the blood, impacting overall health and vitality.

In contrast, the other symptoms listed do not align with the effects of bone marrow syndrome. For example, increased appetite is not typically associated with this condition; rather, patients may experience loss of appetite due to illness. Similarly, improved immunity to infections is incorrect, as bone marrow damage can lead to a reduced production of white blood cells, negatively impacting immune function. Lastly, a heightened stress response is not directly related to bone marrow syndrome and instead may occur due to other factors unrelated to the physiological effects on blood cell production. Therefore, the decrease in red blood cells is the defining characteristic of bone marrow syndrome.