Fiction genre has made-up stuff like magic, witches, wizards, talking animals and so on.
Science fiction is a genre of fiction with imaginative content such as futuristic , science and technology.
Thriller is a genre of the main character facing a problem, a mystery, escape or mission which leads to a stressful climax. It sometimes contains horror or some mystery.
It is when characters in a book, take risks and sometimes there is physical danger. This is the main plot.
The mystery genre is when there is a detective that finds clues to solve a crime. It can be a short story or a series of novels. If it is a series in one or two of the books, it sometimes leaves cliff hangers. It relieves the reader at the end of the book when the detective solves the crime.
realistic fiction is a genre that could happen