Final answer:
The southern region of Africa is called "Sub-Saharan" because it is situated below the Sahara Desert.
Step-by-step explanation:
The term "Sub-Saharan Africa" refers to the region of Africa that lies south of the Sahara Desert. It is called "Sub-Saharan" because it is located below the Sahara Desert, which is a significant geographical feature in Africa. This term is used to distinguish this region from the northern parts of Africa, which are not affected by the desert.
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