Description:

Correct Answer: Relative Humidity

Relative humidity is a measure of how much water vapor is in the air compared to the maximum amount the air can hold at a given temperature. It's expressed as a percentage.

For example:

If the relative humidity is 50%, the air contains half the water vapor it could hold at that temperature.

At 100% relative humidity, the air is fully saturated, and condensation (like fog or dew) is likely to occur.

Why Not the Others?

Dew Point:
This is the temperature at which air becomes saturated and water vapor starts to condense into dew. It tells us how much moisture is in the air but doesn’t compare it to how much the air could hold.

Atmospheric Pressure:
This refers to the weight of the air pressing down on the Earth, measured in units like hPa or mmHg. It’s unrelated to moisture content in the air.

Summary:

Relative Humidity = actual moisture ÷ max moisture capacity × 100%

Affects how hot or cold we feel (why high humidity feels sticky)

Important in weather forecasting, HVAC systems, and agriculture