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 blood from the tissues of the body back to the heart are usually positioned There are a number of differences between veins and arteries. Veins: carry blood from the tissues of the body back to the heart are usually positioned closer beneath the surface of the skin are less muscular than arteries, but contain valves to help keep blood flowing in the right direction, usually toward the heart would collapse if blood flow stops.