Answer the following question given this paragraph: What is this strange-looking object? Can you guess what it is? It's a model of a certain type of matter. Some types of matter are elements, or pure substances that cannot be broken down into simpler substances. Many other types of matter are compounds. The model above represents a compound. The compound it represents is carbon dioxide, a gas you exhale each time you breathe. Q: Which gas do people exhale during each breath? Choices: - carbon monoxide - nitrogen - oxygen - carbon dioxide A:
A:
carbon dioxide