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.
Bone tissue is different from bones themselves â bones are organs made up of bone tissue as well as marrow, blood vessels, epithelium and nerves, while bone tissue refers specifically to the mineral matrix that form the rigid sections of the organ.