Under what circumstances can twins be born in humans?

*a mastectomy is the surgical removal of one or both breasts, either partially of fully. an oophorectomy is the surgical removal of an ovary or ovaries. analyze a woman’s risk of dying of cancer if she carries a mutated brc1 gene. how do heredity and inheritance relate to the data presented in these charts? what data would you need to see in order to draw conclusions about the effectiveness of preventive surgeries? what does the age at diagnosis tell you about the mutation? explain how breast-cancer genes are still present in the population, despite cancer-related surgeries and deaths.