BIOMOLECULES AND ENZYMES

Detailed explanation-1: -RBCs contain hemoglobin (pronounced: HEE-muh-glow-bin), a protein that carries oxygen. Blood gets its bright red color when hemoglobin picks up oxygen in the lungs. As the blood travels through the body, the hemoglobin releases oxygen to the different body parts. Each RBC lives for about 4 months.

Detailed explanation-2: -Human blood is red because hemoglobin, which is carried in the blood and functions to transport oxygen, is iron-rich and red in color.

Detailed explanation-3: -Blood is always red, but the shade of red depends on how much oxygen is in the red blood cells. When you breathe in, you are filling your blood cell with oxygen, and it gives them a very bright red color. As blood travels through your body, it loses the oxygen and takes on carbon dioxide (which you exhale).

Detailed explanation-4: -As blood leaves the heart and is oxygen-rich, it is bright red. When the blood returns to the heart, it has less oxygen. It is still red but will be darker. This darker red appears blue because of how light travels through the skin.