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.
Arteries and veins carry the blood between the organs of the body and the heart. In the tissues, oxygen and carbon dioxide are exchanged between the blood and the cells. This exchange takes place at the organâs capillaries. All body cells need a continuous supply of oxygen to carry out normal functions.