Biochemistry The affinity of hemoglobin for O2 is increased by: A The formation of salt bridges in hemoglobin B The cross linking of the beta chains of hemoglobin C Lowering the pH D Decreases in 2, 3-bisphosphoglycerate (BPG) 💡 Explanation The affinity of hemoglobin for O2 is increased by: ✓ Correct Answer: D. Decreases in 2, 3-bisphosphoglycerate (BPG)