Yeah I believe so but you could spice it up a little bit if you want it's up to you.
I think it is b-idea of meaning.
Answer:
The purpose of the expert is to inform the audience about how water pollution harms humans and aquatic species.
Explanation:
The information that the expert is providing shows specific examples of how though incorrect practices the water has become dangerous for people and the species that live in it. The excerpt has an informative purpose it doesn't try to convince anyone to do or accept anything but it tries to make people see the reality about the world and the dangers we are living now.
Usually what element helps you identify the theme of a story is what lesson the main character learns, or any important idea or refrain throughout the story.
