Why is our blood red

Our blood is red because it contains red pigment called haemoglobin

Our blood is red due the presence of a substance called haemoglobin in our body

Each hemoglobin protein is made up subunits called hemes, which are what give blood its red color. More specifically, the hemes can bind iron molecules, and these iron molecules bind oxygen. The blood cells are red because of the interaction between iron and oxygen.

Blood is always red, actually. Veins look blue because light has to penetrate the skin to illuminate them, blue and red light (being of different wavelengths) penetrate with different degrees of success. What makes it back to your eye is the blue light. Meanwhile, here's what happens to the blood in your body: The heart pumps blood to your lungs to pick up oxygen. The oxygen-rich blood is then pumped out to your body through your arteries. It's bright red at this point. From your arteries, the blood flows through tiny blood vessels called capillaries, where it gives up its oxygen to the body's tissues. Your lips have a lot of these capillaries, which is why they're red. Your blood, now exhausted of its oxygen, is dark red as it now returns to your heart through your veins. This article has been corrected from the original version.

Blood is always red, actually. Veins look blue because light has to penetrate the skin to illuminate them, blue and red light (being of different wavelengths) penetrate with different degrees of success. What makes it back to your eye is the blue light.

Blood is red because of the presence of hemoglobin inside our red blood cells. Hemoglobin is a protein that forms a complex with iron molecules and together they transport oxygen molecules throughout the body. Iron has the property of reflecting red light and because there is so much iron in our blood, blood looks red. When hemoglobin is carrying a lot of oxygen ( when just leaving the lungs), blood is bright red. When most of the oxygen has been released to the body, blood is dark red.