Humans and many animals will endanger or even sacrifice their lives to save another—sometimes the life of another species.a Natural selection, which evolutionists say selects individual characteristics, should rapidly eliminate altruistic (self-sacrificing) “individuals.” How could such risky, costly behavior ever be inherited? Its possession tends to prevent the altruistic “individual” from passing on its genes for altruism? b If evolution were correct, selfish behavior should have eliminated unselfish behavior.c Furthermore, cheating and aggression should have “weeded out” cooperation. Altruism contradicts evolution.d