Answer:
Drought in the Sahel in the 1970s and 1980s made it look like the desert was expanding, because the reduction of rainfall at the desert margin (the Sahel) caused a reduction in vegetation. Warm, moist air rises near the equator, then cools and condenses its moisture, which falls as rain or snow
Answer:
holidays , beliefs or customs passed from generation to the next.
Explanation:
I believe all the above aka 4 because the communities had to much of an over crowding which lead to crime and then a disease broke out which occurs in the 19th century