Why is hemoglobin considered a more efficient oxygen transporter than myoglobin?

• A. Myoglobin exhibits positive cooperativity and releases oxygen more effectively at lower partial pressures.
• B. Hemoglobin has a higher oxygen affinity than myoglobin, making it a better transporter.
• C. Myoglobin has a lower oxygen affinity than hemoglobin, making it a better transporter.
• D. Hemoglobin exhibits positive cooperativity and releases oxygen more effectively at lower partial pressures.

Answer: (D)