Why is blood red? Why not another colour?

Question

What is it that makes blood red and not another colour? What changes in the external environment or our internal human bodies could *possibly* make blood another colour?

Answer 1

our blood is actually blue. It is a chemical reaction with oxygen that makes it turn red when you bleed or something. Thats why our veins are blue.

Answer 2

blood is red because of hemoglobin.The hemoglobin absorbs wavelengths of light in the blue/ yellow region and transmits ( does not absorb ) in the red region of the spectrum. Thus the color seen is the light transmitted by the hemoglobin. For the life of me I cannot understand why some people try to derive totally nonsensical philosophical rubbish from well -defined phenomena of physics, chemistry , etc . Totally ludicrous

Answer 3

This is actually in response to Samu-Kun: Blood is not blue, but red. It is a common myth. The reason our veins appear blue is because of light refraction.  

Answer 4

Blood is red because of hemoglobin in the red blood cells that attract and hold oxygen. Hemoglobin is largely comprised of iron.

Red blood cells, or corpuscles, encased in blood vessels, color the blood. Since there are about 35 trillion of these tiny, round, flat discs circulating in one's body at any one time, their sheer number necessarily lends their red color to the blood.

Answer 5

Yours is a philosophical question; the "why" question. There is no answer to "why" question. Why the colour of the leaves is green? why the universe? why earth moves around the sun? why galaxies exist? why I am living? why I write this answer? why you were born to this earth? why, why, why, there is no tangible answers. We say we just exist because we are. The colour is only a mental perception; the animals sees colours differently from us. So, why the blood is red, has no reliable answer. It is like that.