Which term refers to gases that cannot be seen by the naked eye?

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

Answer: (A)

Visibility is what this item is testing. An invisible gas is one that cannot be seen with the naked eye, so the term that describes gases you can’t see is invisible gases. Odorless and tasteless describe how a gas smells or tastes, not how it looks, so they don’t address whether something can be seen. A gas can be invisible but have a smell, or be colored and therefore visible, which shows that visibility is a separate property from odor or taste. The term that fits the description given is invisible gases.