What is true of an air mass originating from the equatorial region?

An air mass originating from the equatorial region is characterized by high moisture content. This is due to the warm temperatures present in this area, which facilitate a significant amount of evaporation from the surface of the ocean and other bodies of water. As the warm air rises, it collects moisture, leading to the formation of humid air masses that can influence weather patterns.

The other choices do not accurately describe the characteristics of equatorial air masses. For instance, air masses from this region are typically not dry because they contain moisture from the evaporation process. They also do not display extreme temperature changes; rather, they tend to maintain relatively consistent warm temperatures. Lastly, they are not cold; in fact, they are warm due to their origin in a region characterized by high sun angles and intense solar heating.