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.
Organ. An organ is a structure composed of two to four types of tissues working to perform functions that are beyond the scope of an individual tissue type. A set of related organs working cooperatively toward the performance of even more complex functions constitutes an organ system.Organs come in many different forms.ikewise, the blood vessels and nerves in these organs are organs unto themselves. This organ within an organ motif is also exhibited in the sense organs. For example, within the eyeball is an organ called the retina, an association of neural and epithelial tissue that detects light entering the eyeball.