Product Overview: If you need a powerful resource to teach your students human impacts, and eutrophication, or the importance of manatees and biodiversity, you really need to watch this 26 minute documentary from Changing Seas TV on YouTube, which you can see here. Here's how this lesson would go:Students read the facts, and decide if they are true or false, and mark this in the before video column. Students watch the video (as whole group, maybe for homework) and listen for facts as they come u