Who had a 1975 No. 1 hit with "Have You Never Been Mellow"?

Complete the title of the 1975 adventure film starring Sean Connery: "The ___ and the Lion". In 1975 which group took power in Cambodia, beginning a murderous four-year rule? Don Bateman's ground proximity warning system, which the FAA began requiring in the 1970s, was designed for use in what? In "Monty Python and the Holy Grail" (1975), which role did Graham Chapman play? At the end of which 1975 film does police chief Brody say "I used to hate the water... I can't imagine why"? In which 1975 hit does John Denver explain why he's grateful for simple rural life? Who had a 1975 hit with the disco song "Love to Love You Baby"? Which two college dropouts founded Microsoft in 1975?