Answer:
Cash Crop: Agricultural products grown to be sold
Desertification: A change causing an area to become more arid
Homogenous: Of the same kind or type
Shifting agriculture: A farming system in which farmers move when an area's nutrients are used up
Subsistence farming: Growing crops to provide for the needs of one's family
Topography: The physical features of a place or region
There wasn't a vocabulary word for it but the average number of children a woman will have in her lifetime is called the fertility rate.