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.
In human anatomy, the hepatic veins are the blood vessels that drain de-oxygenated blood from the liver and blood cleaned by the liver (from the stomach, pancreas, small intestine and colon) into the inferior vena cava. They arise from the substance of the liver, more specifically the central vein of the liver lobule.