We observe a group of people completing a 5k run together. One person is far ahead of the group and running as fast as they can. The second is running at a moderate speed. The third is switching between running and walking. The last is walking casually without straining themselves. Out of these four, which is likely to have tissues where the binding of oxygen is the lowest? a. The first runner
b. The third runner.
c. The second runner.
d. The fourth runner.