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.
Definition of vein for Students. 1  1 : one of the blood vessels that carry the blood back to the heart. 2  2 : a long narrow opening in rock filled with a specific mineral a vein of gold. 3  3 : a streak of different color or texture (as in marble) 4  4 : a style of expression I continued in a more serious vein.