Consider the oxygen-binding profile at three different pH values of 7.6, 7.4, and 7.2. Which statement is most correct?
1) The oxygen-binding affinity decreases as the pH decreases.
2) The oxygen-binding affinity increases as the pH decreases.
3) The oxygen-binding affinity is not affected by changes in pH.
4) The oxygen-binding affinity is highest at a pH of 7.4.