When you take Material or Fuel, you may place it in your Captives. (Even if you're taking for the Imperial Trust!)
Material and Fuel in your Captives are frozen. (They add to both Tyrant and Tycoon, and they return to the supply if Tyrant is scored.)
Act: 3
A: They are returned to the general supply.
A: Your resources in your Captives box are still Captives, but they are no longer frozen.