How you can say that social difference based on accident of birth in our live?

These social differences are mostly based on accident of birth. Normally we don’t choose to belong to our community. We belong to it simply because we were born into it. We all experience social differences based on accident of birth in our everyday lives. People around us are male or female, they are tall and short, have different kinds of complexions, or have different physical abilities or disabilities. But all kinds of social differences are not based on accident of birth. Some of the differences are based on our choices. For example, some people are atheists. They don’t believe in God or any religion. Some people choose to follow a religion other than the one in which they were born. Most of us choose what to study, which occupation to take up and which games or cultural activities to take part in. All these lead to formation of social groups that are based on our choices.