Choose the sentence that does not belong in the paragraph. (1) The long eerie songs of humpback whales are a great mystery to humans. (2) If you have ever been on a whale watch, you may have been lucky enough to see these magnificent creatures surfacing and diving. (3) Each year, after swimming the world's wide oceans, humpback whales return to their sheltered winter waters singing a new song. (4) The song, which may be 30 minutes long, is filled with gliding scales and sighs, throbbings, thrummings, and clicks. (5) It seems impossible that any creature could remember it, yet all of the humpbacks in one part of the ocean can repeat the same song, and every year the song is a little bit different. (6) No one knows why