Which U.S. city hosted the first World's Fair held in America in 1876, celebrating the country's centennial?

Philadelphia

What is the name of the fictional high school featured in the musical film "Grease"? Which land mammal is known for secreting reddish, sunscreen-like fluid from its skin under intense sunlight? Which company developed Fortnite? In boxing, what term refers to fighting at close quarters? If two angles are complementary and one angle is 45°, what is the other angle?