The answer is:
- an idea of what makes someone a hero
- a characetiristc of a hero
Why?
Let's check the given options in order to discard what is included or not in the response :
An idea of what makes someone a hero: This idea has been included where we read "Heroes are people who improve other people's lives without asking for anything in return". Improving other people's lives and Helping them without asking for anything in return is what makes a hero.
An example of a hero: This hasn't been included here. An example of hero would include someone's name, or alias and would explain what does that "hero" do to be considered a "hero"
A characteristic of a hero: This idea has been included where we read: "may risk their own safety to make the world a better place". Since it could be taken as a description, it can be taken too as a hero's characteristics, since (according to this context) heroes have specific characteristics which can not be confused.
Have a nice day!
