(i) Generally, social differences are based on accident of birth. We do not choose our religion, we are born to it. It depends on the religion followed by our family. Our looks, our physical attributes, our complexions, our gender, or even our abilities and disabilities are not based on our choice. The friends, neighbours, all depend on the family we are born into. (ii) The second difference is based on our choices. For example, (i) We may not believe in any God or religion and become an atheist by choice. (ii) We may even change our religion when we grow up. (iii) We have the choice to choose our own area of study, different from that of our parents, we may choose a different occupation, different cultural activities. These differences lead to formation of different social groups based on our choices.