Who is considered the greatest chess player ever by many and held the World Championship title from 1985 to 2000?

Garry Kasparov

Who starred in and directed the film "A Star is Born" (2018)? In Greek mythology, cornucopia is derived from the horn of which animal? In what year did Canadian Confederation occur? What type of angle measures less than 90 degrees? What's the smallest square number greater than 100?