Guns, Germs and Steel
The Fertile Crescent (an area now mostly in Iraq, Syria and Turkey) was the first place where humans learned to farm. China and New Guinea were also early places where humans learned to farm. Later, farming also began in other regions. However, some regions had more useful crops than others. Crops were more useful if they had more nutritious, meaning they had things like proteins that humans need from their food. They were also more useful if they were easier to grow and were less likely to fail in bad weather. This is why crops from the Fertile Crescent and China spread a long way, while those from New Guinea did not spread far from the island.