Why were the jobs in each region different ?

Because of what resources and challenges each region present. For example, there is a large amount of jobs like shipping in port cities like New Orleans because of how close it is to the water which makes it a prime place for fishing and the transferring of materials. But in some cities, there is a large population, growing by the number, which means there more of a need for housing and public services, so careers like architecture and service jobs are needed to accommodate.