Misc: In 1945 V-J Day; formal surrender of ---------- aboard USS Missouri. ?

Questions

what long-running broadway musical introduced the song "try to remember"?

how many rings make up the olympic symbol?

eleutherophobia is a fear of ___________?

what composer wrote the opera 'tosca'?

which character sang "come out, come out, wherever you are" in "the wizard of oz"?