The best answer would be letter D There are inheririted genes for such behaviour sociobiologist explain altruism as a way of behave since very little ages. This sentence makes reference to natural selection , too . It is believed that in altruists groups evolution happens to all members of the group and that they behave it is affected by their genes. Darwin has explained this with animals that live in communities such as bees they pass al their lives taking care of the queen no matter what. so with that example we can eliminate answer A which mentions that everyone expects something . There is a theory that joins natural selection and altruism as a way of surviving more animals can produce more things and staying together would be safer so B would be incorrect because it does not convert into positive feeling and finally the letter c would not be the best because it mentions society and it would be incorrect to generalize different types of social groups .
