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.
organs in the human body functions location definition of organs an organ is a structure that contains at least two different types of tissue functioning together for a common purpose there are many different organs in the body the liver kidneys heart even your skin is an organusually there is a main tissue and sporadic tissuesthe main tissue is the one that is unique for the specific organ for example main tissue in the heart is the myocardium while sporadic are the nerves blood connective etcfunctionally related organs often cooperate to form whole organ systems there are 10 major organ systems in the human bodyhere are many different organs in the body the liver kidneys heart even your skin is an organ usually there is a main tissue and sporadic tissues