How does the concept of challenges connect to the concept of heroism ?

People have to over come many difficult things to be considered a hero. In books, the hero defies the odds to save the world. Soldiers risk their lives to give others a better chance and to protect their country. Fighter fighters risk their lives to rescue people from their blazing homes. Police officers stand up against those risking the lives of others to ensure safety. None of these brave people could become heroes if there wasn't a challenge to face.

they wouldn't be heroes if there weren't challenges