Social solidarity is when we all work together as a big group to make sure everyone is happy and safe. We do this by caring about each other and helping each other out when we need it.
Think of it like playing a game with your friends. When you play together and help each other out, everyone has a fun time and no one feels left out. But if someone is mean or doesn't play by the rules, it can ruin the game for everyone.
The same goes for our society. When we all work together and care about each other, we can create a happy and safe community. But if people are not kind or helpful to each other, it can make life difficult for everyone. So, it's important that we all work together to be good to each other and make the world a better place.