tv/ movies: who played alexis carrington in the tv series 'dynasty'?

Questions

robert heinlein: rah never owned a farm, but often used this pen name?

70s: this famous idaho dam went to pieces in 1976.?

70s: oregans trojan was the most powerful one of these in this decade.?

70s: this nation tried the "gang of four"?

70s: russian dancer who defected in 1974.?