Question

why is the colour of blood vessels blue rather the colour of blood is red​

Answer 1

The colour of blood vessels is blue because some of the blood vessels carry deoxygenated blood that contain carbon dioxide. So, colour of dexygenated blood appear blue. Vena cava and pulmonary artery carry deoxygenated blood.

Hope it will help u.

Answer 2

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. ... The oxygen-rich blood is then pumped out to your body through your arteries. It's bright red at this point.