[Solved] Why do some people have unusual chromosome combinations,such as XYY and XXX? A) Genetic disease causes a spontaneous increase in the number of sex chromosomes in mature gametes. B) Errors occurred in chromosome segregation during meiosis in their fathers or mothers. C) People who inherit large numbers of short tandem repeats (STRs)also inherit extra sex chromosomes. D) A mistake in mitosis during embryonic development leads to extra sex chromosomes in every cell. E) It is not known why these unusual chromosome combinations occur. Reproductive Costs: The energetic, social, and health-related expenses incurred by an organism to produce offspring. Evolutionary Psychology: The field of research exploring how evolution shaped human psychology. Neuroticism: null Neuroticism: A personality trait involving a long-term tendency to be in a negative emotional state. People high in neuroticism are more likely to experience feelings of anxiety, sadness, and moodiness.