Which logical fallacy is used in the text?
Mrs. Hatfield, you point out that childhood obesity rates have skyrocketed, but are you aware that rainforests provide critical habitats for some of the world's rarest plants and animals?

 - straw man: a misrepresentation of an opponent's position that makes it easier to argue against
 - red herring: the use of a completely unrelated topic or idea
The text argues that obesity rates and rainforests are somehow interconnected. However, these two ideas aren't related. This illustrates a type of logical fallacy known as a red herring.