The phase of matter at room temperature depends on the specific substance you're talking about. Here's a breakdown:

* Room Temperature: This is generally considered to be around 20-25 degrees Celsius (68-77 degrees Fahrenheit).

* Phases of Matter: The three common phases are solid, liquid, and gas.

Examples:

* Water: At room temperature, water is a liquid.

* Iron: At room temperature, iron is a solid.

* Oxygen: At room temperature, oxygen is a gas.

Important Note: Some substances can exist in different phases at room temperature depending on pressure. For example, carbon dioxide can be a solid (dry ice) or a gas at room temperature, depending on the pressure.

Let me know if you want to know the phase of a specific substance at room temperature!