Answer: The bone marrow.
Step-by-step explanation:
Leukemia represents a group of malignant neoplasms derived from hematopoietic cells. This disease always starts in the bone marrow, where the blood cells are produced, and later invade the peripheral blood, being able to reach several organs of the affected patient. According to the cell of origin, leukemias can be classified as a myeloid or lymphocytic disease. Remembering that myeloid cells will originate erythrocytes (red blood cells), monocytes, neutrophils, eosinophils, basophils and platelets, and lymphoid cells originate lymphocytes.
Due to the reduction in the number of erythrocytes and, subsequently the oxygen transport capacity of the blood, patients with leukemia develop anemia and fatigue. Leukemic patients also have easy bleeding due to lack of platelets (thrombocytopenia). Fever is also a factor and is associated with infection due to neutrophil depletion.