The supporting material is called an extended example.
Explanation:
An extended example may be a narrative or way of supporting your argument in your speech. For instance, when you are telling a story and you need to strengthen or to reduce the complexity of some certain concepts. You can use a personal story or a narrative to strengthen and clarify your ideas, while in the same vein you are also making a personal connection with your audience.
He enjoys music that is more authentic and less mainstream.
Explanation:
Based in the passage, we can assume that Mateo dislikes pop music, so you can also assume that Mateo likes music that is less popular, thus more authentic and less mainstream.
