The species theory, polygenism, held that human races were of different lineages and suggested a hierarchy outlined in the Chain of Being that positioned Africans between man and lower primates.
No, they are involved in the Circulatory System which is responsible for pumping and channelling blood to and from the body and lungs with heart, blood and blood vessels. no veins are not considered an organ because they are a grouping of different tissues like a organ.
Key point: the oxygen-rich blood vessels entering an organ are called arteries, while the oxygen-depleted blood vessels leaving an organ are called veins. So a blood vessel entering the liver or kidneys would be an artery. A blood vessel leaving the liver or kidneys would be a vein. The liver attribute is hepatic ( for example, the working cell unit in the liver is the hepatic cell), while the kidney attribute is renal (for example, renal failure).