This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Surgery
[{'content': 'What is a xenograft: September 2010 \nSelect and explain. \nA. Graft from 1 twin to other twin, B. Graft from 1 species to other species, C. Graft from father to other child, D. Graft from sister to brother', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. B: Graft from 1 species to other species Xenotransplantation is the transplantation of living cells, tissues or organs from one species to another, such as from pigs to humans. Such cells, tissues or organs are called xenografts or xenotransplants. In contrast, the term allotransplantation refers to a same-species transplant. Human xenotransplantation offers a potential treatment for end-stage organ failure, a significant health problem in pas of the industrialized world. It also raises many novel medical, legal and ethical issues. A continuing concern is that pigs have shoer lifespans than humans: their tissues age at a different rate. Disease transmission (xenozoonosis) and permanent alteration to the genetic code of animals are also causes for concern.', 'role': 'assistant'}]