Percentage of CO2 carried as carboxyhaemoglobin is_________?

Explanation

About 20% to 23% of transported carbon dioxide forms carbaminohaemoglobin by binding to haemoglobin, so 20% is the suitable option. Most carbon dioxide, about 70%, is transported as bicarbonate ions, while about 7% remains dissolved in plasma. Students often choose 70% because it is the largest percentage, but that represents bicarbonate transport, not carbaminohaemoglobin.