<prompt> An 18-year-old man is recently diagnosed with beta-thalassemia minor. His hemoglobin is 10.5 gdL, and he feels well. Which of the following findings is characteristic of this condition?an increased amount of fetal hemoglobin HbF or hemoglobin A2 HbA2increased osmotic fragility of the red cellsabsent bone marrow ironincreased macroglobulins in the serum  <response>: An increased amount of HbF or HbA2 would be expected. As beta-chains are decreased in beta-thalassemia, the excess alpha-chains combine with gamma- and delta-chains to make HbF and HbA2, respectively. 