Which of the following factors affects absolute humidity and dew point?

Absolute humidity is defined as the mass of water vapor present in a given volume of air, whereas dew point represents the temperature at which air becomes saturated with moisture and water vapor begins to condense into liquid. The level of water content in the air directly influences both of these measures.

When there is a change in the water content of the air, it directly alters the absolute humidity. For instance, if more water vapor is added to the air (such as through evaporation), absolute humidity increases because there is more water vapor for a given volume of air. Additionally, an increase in water vapor also raises the dew point, as more moisture in the air means that it will reach saturation at a higher temperature, resulting in a higher dew point.

Therefore, water content is crucial in determining both the absolute humidity and the dew point, making it the correct answer in this context. Changes in air temperature, altitude, or pressure variation can influence the ability of air to hold moisture, but they do not affect the absolute humidity or dew point directly in the same way that variations in water content do.