Well kiddo, humans are all one species, just like all dogs are one species - even if some dogs look very different from other dogs. But some people like to talk about different "types" or "races" of humans, and they call these types "subspecies".
But scientists say that these different types of humans are not really different enough to be called subspecies. That's because - even though we look different on the outside - our DNA on the inside is very similar. In fact, scientists have found that all humans are 99.9% identical in their genetic makeup!
So, even though people may look different because of things like skin color, eye shape, and hair type, we are all just humans - members of the same species - and that's what really matters! We should all be kind and respectful to each other, no matter what we look like on the outside.