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.
Close examination of a healthy organ reveals a lining of several layers of cells. The layers do not contain any blood vessels and one surface of the cells lines the cavity of the organ. This tissue is a type of. epithelium.