Exercise will result in the production of co2, which will acidify the blood. explain the buffering system that minimizes blood ph changes.

The carbon dioxide carried in the blood is actually combined with water and carried in the red blood cells in the form of carbonic acid, which has a dissociation constant:

H₂CO₃ ↔ H⁺ + CO₃⁻

When the pH of the blood decereases, the concentration of H⁺ ions in the blood becomes high. This causes the equilibrium to shift backwards, as per Le Chatelier's principle. The H⁺ ions are converted back to carbonic acid and the pH is increased. The opposite occurs when the pH is too high.

The answer is d. when it begins to fall back to the child's hand