question: A science teacher filled one balloon with helium gas and a second balloon with carbon dioxide. The helium-filled balloon rose to the ceiling, and the balloon filled with carbon dioxide fell to the floor. Which statement is an inference based on this demonstration?
choices.text: Each balloon behaved differently. Helium gas has a lower density than air. Carbon dioxide causes a balloon to expand. Balloons can be filled with different gases.
choices.label: A B C D