Have you ever heard of someone being a superhero and always saving the day? Well, in some ways, people who have certain jobs also have a duty to protect people. This means that they have to make sure that the people they work with or for are safe and secure.
For example, if you go to school, your teacher has a duty to protect you from danger. They will make sure that you are safe when you are in the classroom or on the playground.
Another example is a doctor. They have a duty to protect their patients by making sure that they get the right medicine and treatment for their illness or injury.
Even police officers have a duty to protect people. They make sure that everyone follows the rules and that people who break the rules are punished to keep everyone else safe.
So, duty to protect means that some people have jobs that require them to make sure that the people they work with or for are safe. It's like being a superhero, but with a job!