What is then main purpose of the following passage. unlike plastic bags, paper bags are made from renewable source not from oil. people should use more paper bags.

dramatic irony occurs when the reader/audience knows more about a character's situation than the character does. the one main effect is that it gives the reader a sense of superiority, or detached superiority. the reader not only seemingly discovers what is revealed, but feels superior for doing so.

the type of supporting detail is fact!