Race is a word that people use to try and describe different groups of people based on things like how they look, where they come from, and their skin color. This can be really confusing because there are lots and lots of people in the whole world, and everyone is unique in their own way.
Scientists who study biology have found that there's really not much difference between the different races of people. That's because we all belong to the same species, which means we can all have babies with each other and create new, healthy humans. You know how different dogs can look really different from one another - like some dogs have long hair and some dogs are bigger than others? But even if they look really different, they are still all dogs. We can say the same thing about humans - people might look really different on the outside, but on the inside they are still all humans.
It's important to remember that people have been treated unfairly because of their race for many, many years. Some people have even been treated like they are less important or valuable than others, which isn't right at all. We should always treat everyone with kindness and respect, no matter what they look like or where they come from.