Read the following passage written by a teen hero: I want to be a vocal advocate for nature.
I reject the idea that I am too young to make a difference.
I recently helped a group with a river cleanup.
I was mortified to see the destruction of animals and plants.
When I got home, I composed a letter to my state politicians and asked them to allocate more money to the local river cleanup effort.
I believe my vocation is to help citizens see that we are at a junction.
We can decide to subject nature to abuse, or we can decide to be a benefactor to nature.
I won't let obstacles detract from my mission.

In sentence 4, the root in the word "mortified" means
frustration
death
disappointment
sadness