You can take "in fact" out of the sentence to help with determine what type of sentence it is because it's a prepositional phrase. This leaves us with "Only a small percentage of Southern Africa is desert" which is a simple sentence.
Answer:
2.) Mid adolescence (ages 13-15)
Explanation:
In mid adolescence, during the late middle-school and early high-school years, most rebellion is about creating needed differentiation to experiment with identity and needed opposition to gather power of self-determination.