My teacher brought in her dog who was playing with a snake. It is possible that she brings in her pets but it hasn't actually happened so it would be considered realistic fiction.
This is a book about parts of the human body. This is informational because it is talking about the parts of the ahuman body.
The princess told her dragon that the visitor was a guest and not someone who is trying to hurt her. This is a fantasy because there is no such thing as a dragon. This scenario is very unlikely which makes it a fantasy.