MCU Quiz: The Progressively Harder Iron Man Quiz

Iron Man 2008 Tony Stark Robert Downey Jr.
Marvel Studios

14. What Was The Arc Reactor's Core Made Of That Was Poisoning Tony Stark Before He Replaced It?

Palladium

Polonium

Promethium

Protactinium
Contributor

Jen Gallie hasn't written a bio just yet, but if they had... it would appear here.