How does cellular respiration in tissues contribute to hemoglobin's oxygen release?

• A. Cellular respiration decreases CO2 levels, increasing hemoglobin's oxygen affinity.
• B. Cellular respiration has no effect on hemoglobin's oxygen release.
• C. Cellular respiration increases oxygen concentration, enhancing hemoglobin's oxygen binding.
• D. Cellular respiration produces CO2, which diffuses into the bloodstream and decreases hemoglobin's oxygen affinity.

Answer: (D)