The biblical question "Can the leopard change his ___?" means something is impossible. What are the missing words?

Camilla Parker Bowles was born Camilla Shand on July 17, 1947, in which city? Which candidate defeated Hubert Humphrey in the 1968 U.S. presidential election? In 1990, Campbell launched a new cream soup made from which vegetable famously disliked by President George H.W. Bush? Camus' attack on Stalinism in his 1951 book "The Rebel" strained his relationship with which existentialist? Which 1969 rock opera by the Who is about a "deaf, dumb and blind kid" who becomes a pinball champion? Canada issued a series of ten sterling silver coins marking which 1988 event in Calgary? Which is Canada's smallest province by area? Canada's first full-scale plant of which controversial type of power opened on Lake Huron in 1967?