The expression "the air is saturated" means ____________.

The phrase "the air is saturated" specifically describes a condition where the air holds the maximum amount of water vapor it can at a given temperature and pressure. This state is defined by a relative humidity of 100%. When relative humidity reaches this level, the air cannot accommodate any additional moisture, which means it has reached its saturation point. At this stage, any added moisture may lead to condensation, forming dew, fog, or precipitation.

While the other choices present scenarios related to moisture and temperature, they do not accurately encapsulate the definition of air saturation. For instance, a relative humidity of 50% indicates that the air is holding only half of the moisture it could potentially contain, and the temperature being at freezing does not inherently mean the air is saturated. Likewise, stating the air can hold no more moisture is vague without specifying the context of relative humidity being 100%.