Visible Moisture includes which of the following forms?

• A. Fog with visibility of one mile or less
• B. Dust or sand in the air
• C. Clear skies
• D. Dry ice

Answer: (A)

Visible moisture is moisture in the air that you can actually see, such as fog. Fog forms when tiny droplets suspend in the air and reduce visibility to about one mile or less, which is why this option fits the idea of visible moisture. Dust or sand in the air are dry particulates, not moisture. Clear skies indicate no visible moisture at all, and dry ice is a solid, not moisture in the air. So fog with reduced visibility best represents visible moisture.