Misc: What is the name for a line of longitude on a map?

Questions

In 1971 Abu Dhabi, Ajman, Dubai, Fujeira, Sharjah & Umm ak Qiwain form the United ---------- Emirates. ?

In 1973 ---------- Seles tennis star (French Open-1990), born. ?

In 1975 Laos People's ---------- Republic founded (National Day). ?

In 1982 1st permanent artificial ---------- successfully implanted (U of Utah) in retired dentist Barney Clark; lived 112 days with the Jarvic-7 heart. ?

In 1986 Desi ---------- actor (Ricky Ricardo-I Love Lucy), dies at 69. ?