NEET BIOLOGY

Detailed explanation-1: -When blood comes into contact with air, it goes through a natural process called oxidation. Hemoglobin is a blood compound that transports oxygen and contains iron. When this iron is exposed to air and oxygen, it becomes iron oxide (the same compound as rust), which has a darker brown color.

Detailed explanation-2: -Blood in the human body is red regardless of how oxygen-rich it is, but the shade of red may vary. The level or amount of oxygen in the blood determines the hue of red. As blood leaves the heart and is oxygen-rich, it is bright red.

Detailed explanation-3: -The color of human blood ranges from bright red when oxygenated to a darker red when deoxygenated. It owes its color to hemoglobin, to which oxygen binds.

Detailed explanation-4: -Oxygenated (arterial) blood is bright red, while dexoygenated (venous) blood is dark reddish-purple.