11. When Joe put a cheeseburger sealed in a plastic bag into the microwave, there was not much air in the bag. After the cheeseburger was heated, the plastic bag was full of air. Where did the air come from? A. It came from a chemical reaction whereby energy from the microwave creates oxygen molecules.
B. It came from the fan in the microwave.
C. It came out of the cheeseburger.
D. It was already in the bag and it expanded outward when it was heated.