You are presented with the quiz "Some what enclosures convert electricity into light and heat energy?" 

But you don't know the answer, so you turn to your teacher to ask for hints. He says that "some light bulbs convert electricity into light and heat energy" and "household light bulbs are evacuated glass enclosures with wires leading to a tungsten filament". 

So, what's the best answer to the question?


 

  glass         