<prompt> A 47-year-old man presents with a 6-week history of increasing fatigue and dark-colored stools. Complete blood count shows hemoglobin of 8.6 gdL and microcytic, hypochromic RBCs. Upper gastrointestinal endoscopy reveals a peptic ulcer along the lesser curvature of the stomach. This patients anemia is most likely caused by deficiency of which of the following?Folic acidIronThiamineVitamin B12  <response>: Gastrointestinal hemorrhage leads to the loss of heme iron at a rate faster than it is replaced from dietary sources. The result is microcytic hypochromic anemia. The anemias associated with deficiencies of folic acid choice A and vitamin B12 choice D are macrocytic.Diagnosis: Iron-deficiency anemia 