What book are you talking about? :)
Answer: The wetlands on the Gulf Coast are being preserved because the environment has been drastically altered by humans. Extreme weather due to climate change has caused extreme droughts then flash floods. Moreover, oil spills have been known to happen there, causing ocean dead zones and killing life in that area.
1. Exodus means that there a mass departure of people leaving
2. A noun is a word that describes a person, place, or thing