The temperature to which humid air must be cooled at constant pressure to become saturated is called what?

The correct answer is related to a key concept in meteorology and atmospheric sciences known as the dew point. The dew point is specifically defined as the temperature at which air becomes saturated with moisture and water vapor starts to condense into liquid water, forming droplets or dew.

When humid air is cooled at a constant pressure, its capacity to hold moisture decreases, and at the dew point temperature, the air is fully saturated. This is a critical concept for understanding weather formation and cloud development, as reaching the dew point is essential for the formation of clouds and precipitation.

The other options do not accurately define this process. 'Humidity point' is not a recognized term in meteorology, and 'temperature threshold' is a vague phrase that does not convey the specific process of saturation. Meanwhile, 'condensation point' is not a standard term used to refer to the temperature at which saturation occurs; this term can refer to any temperature where a gas may condense into a liquid, but does not specifically address the concept of saturation relative to humidity. Thus, the dew point is the most precise term for this phenomenon.