question: Solid carbon dioxide is called what?
distractor3: blue ice
distractor1: carbohydrate
distractor2: liquid nitrogen
correct_answer: dry ice
support: Solid carbon dioxide is called dry ice because it does not pass through the liquid phase. Instead, it does directly to the gas phase. (Carbon dioxide can exist as liquid but only under high pressure. ) Dry ice has many practical uses, including the long-term preservation of medical samples.