Question: why is deoxygenated blood blue?
Answer: Color. The color of human blood ranges from bright red when oxygenated to a darker red when deoxygenated. ... Deoxygenated blood is darker due to the difference in shape of the red blood cell when oxygen binds to haemoglobin in the blood cell (oxygenated) versus does not bind to it (deoxygenated). Human blood is never blue ...