Why is through the tunnel a coming of age story

Through a Tunnel is a coming of age story because it follows the life of the protagonist, starting from his early life, to his adulthood. We see everything that happens in his life throughout the story, how all of these events combine to shape his life and his personality, and how he grows into an adult human being. 

A

Explanation:

Mirth means ¨amusement, especially expressed as laughter.¨