You are presented with the quiz "What does heat and pressure change into natural gas?" 

But you don't know the answer, so you turn to your teacher to ask for hints. He says that "heat and pressure change the remains of prehistoric living things into natural gas" and "dinosaurs and Other Prehistoric Creatures Dinosaurs are just one group of prehistoric animals". 

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


 

      remains of dinosaurs     