Which term refers to water in the gaseous form?

• A. Water vapour
• B. Boiling point
• C. Evaporation
• D. Steam

Answer: (D)

The main idea is understanding the form water takes when it becomes a gas. Steam is the term often used for water in the gaseous state that comes from heating or boiling. It describes the gas emitted from water as it turns to vapor, and in everyday language it’s the familiar label for that gaseous water, especially when you can see it as a mist above boiling water.

Water vapor, while scientifically the precise term for water in the gaseous phase, is the general description of gas water, whereas steam emphasizes the bubbling, boiling source of that gas. The boiling point is simply the temperature at which a liquid begins to boil, not the state itself, and evaporation is the process of a liquid turning into gas at the surface, not a named form.

So steam is the best fit because it explicitly names water in gaseous form produced by heating.