With the A. migration of people from fertile areas, knowledge of agriculture spread by diffusion.
When people migrate from a place, they move into other areas. When something diffuses, it spreads around. 
        
             
        
        
        
11. ireland's (beautiful landscape)inspired her many writers and artists. 
i hope this helps you out
        
             
        
        
        
It effects everyone because their is no currency to spread around, to trade, or to buy stuff.