THE AMOUNT OF PRECIPITATION
The amount of precipitation that a place receives depends on the air masses and the source region that influences the amount of water vapor content in the air mass.
Certain places on the earth have extremely heavy precipitation, while other large areas receive insufficient precipitation for most common human activities.
Countries in desert regions can support large populations if they have access to water. i.e. Egypt , the Nile River brings water from a region with abundant moisture to a dry area, conversely, tropical areas such as the Amazon region of Brazil receive so much rain that lush vegetation and disease have hindered development, including tourism