Which term describes gases that the naked eye cannot detect?

• A. Invisible Gases
• B. Odorless
• C. Tasteless
• D. Imminent

Answer: (A)

The idea here is about visibility. Gases that you cannot detect with the naked eye are described as invisible gases. Odorless and tasteless describe lack of smell or taste, which are senses other than sight, so they don’t address whether the gas can be seen. Imminent is unrelated to detectability. So the term that fits gases you can’t see without tools or warning is invisible gases.