It is 100% the right answer. Just because you are checking pH in blood doesn’t mean it suppose to change when you get sick or something. As people in this have said .2 pH is the most change you will see in the human body, anything more than that change you body literally cannot function. Cells would be destroyed very quickly.

This is the right answer. pH should not change in your body unless you have some really serious problems. Even pH in water is relatively consistent when talking about bodies of water. If pH drops in water then it leads to coral bleaching and kills off living things that would need a stable pH. Many things adapt to the pH in their environment.