Question

wjy do veins appear bue in colour when they carry blood which is red in colour

Answer 1

It all has to do with the science of light. The colors we see are the result of which wavelengths of light are reflected back to our eyes. Veins appear blue because blue light is reflected back to our eyes. ... The oxygen-depleted bloodthat veins carry also tends to absorb red light more thanblue light.

Answer 2

Veins are actually dark red in colour because they have carbon do oxide mixed in blood in large quantities which makes them dark red in colour but in diagrams veins is shown in blue in colour just to clearly distinguished between artery & vein

Hope it helps!!