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.
Veins carry deoxygenated blood from the tissues to the heart and remain contracted if there is no blood inside the vessels. Veins run close to the skin, and these generally thin structures contain valves to keep the flowing direction always towards the heart.