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.
Vein, in human physiology, any of the vessels that, with four exceptions, carry oxygen-depleted blood to the right upper chamber (atrium) of the heart. The four exceptionsâthe pulmonary veinsâtransport oxygenated blood from the lungs to the left upper chamber of the heart.