Chapter 18, Problem 8RQ

During very heavy exercise, the

1. pH increases

2. ${\text{Pa}}_{{\text{CO}}_{\text{2}}}$ decreases

3. ${\text{Pa}}_{{\text{O}}_{\text{2}}}$ remains constant

4. pH decreases

5. ${\text{Pa}}_{{\text{CO}}_{\text{2}}}$ increases

A. 1 and 2 only

B. 4 and 5 only

C. 2 and 4 only

D. 2, 3, and 4 only