Which sentence is an example of a formal tone in an informative essay on wetlands?

Wetlands need fresh water to survive. They need nutrients. They need sediments, too.
I think it’s a shame that people don’t know more about wetlands and how they can survive.
Wetlands are cool ‘cause they’re made up of all of this crazy stuff, like nutrients and sediments.
To remain in good condition, wetlands require fresh water, nutrients, and sediments from rivers.