What is a plaster cast made of a living person's face called?

What is a scientist who studies plants called? A plaque in Yankee Stadium's Monument Park honors which former cardinal for a 1979 event held at the stadium? A plaque in the Louisiana State Capitol marks the site of which violent event of September 8, 1935? A plaque left on the Moon in July 1969 has the signatures of Neil Armstrong, Buzz Aldrin and which two other men? A platypus was one of the mascots of the 2000 Summer Olympics in which city? What is a play area for very young children, and also a franchised children's TV show begun in 1953? What is a playing card with two spots called? Which playwright wrote the line "We are all born mad. Some remain so"?