What type of air mass is associated with the great deserts of the Earth?

The correct answer is Continental Tropical. This type of air mass is characterized by being warm and dry, typically forming over hot, arid land areas such as deserts. The formation of Continental Tropical air masses is influenced by the high temperatures and low moisture levels of these regions, which do not have significant bodies of water to provide humidity. As a result, they contribute to the hot and dry conditions typical in desert environments.

Continental Tropical air masses can lead to clear skies and are often associated with high-pressure systems where the atmosphere is stable. This stability is conducive to the dry conditions found in deserts as moisture is not replenished.

In contrast, other air mass types mentioned are associated with different climatic conditions. For example, Maritime Tropical air masses bring warm, moist air from oceanic sources, contributing to humid conditions, while Continental Polar air masses are cold and dry, typically originating from high-latitude land areas. Maritime Polar air masses bring cool, moist air from ocean areas, which also does not align with the characteristics of desert environments.