Q: Which system in the body exchanges gases with the outside air? Choices: - immune - digestive - vascular - respiratory A:
respiratory

Q: What pulls skydivers towards the earth? Choices: - momentum - impact - inertia - gravity A:
gravity

Q: What are the most common types of compounds found on earth? Choices: - sodium - based compounds - ionic compounds - hydrogen-based compounds - carbon-based compounds A:
carbon-based compounds