Where is the respiratory pigment in human body present?AIn white blood cellsBIn red blood cellsCIn both plasma and white blood cellsDIn blood plasmaAnswer: B. In red blood cells Read Explanation: A respiratory pigment is a substance that enhances the capacity of blood to carry oxygen. Hemoglobin is a protein molecule present in red blood cells (RBCs).In humans and other mammals, the most common respiratory pigment is hemoglobin. This protein uses iron to increase the oxygen-carrying capacity of our red blood cells. The interaction between iron and oxygen is what causes our blood to look red. Read more in App